MENDELISM  . To define what some biologists

call Mendelism briefly is not possible . Within recent years there has come to biologists a new idea of the nature of living things, a new conception of their potentialities and of their limitations; and for this we are primarily indebted to the work of Gregor Mendel . Peasant boy, monk, and abbot of Briinn, this remark-able man at one time interested himself in the workings of heredity, and the experiments devised by him and carried out in his cloister garden are to-day the foundation of that exact knowledge of the physiological process of heredity which biologists are rapidly extending in various directions . This extension Mendel never saw . Born in 1822 he published the account of his experiments in 1865, but it was not until 1900, eighteen years after his death, that biologists came to appreciate what he had accomplished . That year marked the simultaneous rediscovery of his work by three distinguished botanists: Hugo de Vries, C . Correns and E . Tschermak . Thenceforward Mendel's ideas have steadily gained ground, and, as the already strong body of evidence in their favour grows, they must come to exert upon biological conceptions an influence not less than those associated with the name of Darwin . - Dominant and Recessive.—Mendel chose the common pea (Pisum sativum) as a subject for experiment-, and investigated the effects of crossing different varieties . In his method he differed from previous investigators in concentrating his attention on the mode of inheritance of a single pair of alternative characters at a time .

Thus on crossing a tall with a

dwarf and paying attention to this pair of characters alone, he found that the hybrids (or F1 generation) were all tall and that no intermediates appeared . Accordingly he termed the tall character dominant and the dwarf character recessive . On allowing these hybrids to fertilize themselves in the ordinary way he obtained a further generation which on the average was composed of three tails to one dwarf . Subsequent experi- ment showed that the T x D P dwarfs always bred true, as did also one out of every three tails; the two remaining tails behaved as the original hybrids in D .. Fs giving three tails to one dwarf . Having regard to D F the characters, tallness { 3 and dwarfness, three and only three kinds of peas exist, viz. dwarfs which breed true, tails which breed true, and tails which give a fixed proportion of tails and dwarfs . The relation between these three forms may be briefly summarized in the subjoined scheme, in which pure tall and dwarf are represented by T and D respectively, while [T] denotes the tails which do not breed true . Experiments were also made with several other pairs of characters, and the same mode of inheritance was shown to hold good throughout . Unit-Characters.—As Mendel clearly perceived, these definite results lead inevitably to a precise conception of the consti- tution of the reproductive cells, or gametes; and to appreciate fully the change wrought in our point of view necessitates a brief digression into the essential features of the reproductive process . A sexual process (see SEx) is almost universal among animals and plants, and consists essentially of the union of two gametes, of which one is produced by either parent . Every gamete contains small definite bodies known as chromosomes, and the number of these is, with few known exceptions, con- stant for the gametes of a given species . On the fusion of two gametes the resulting cell or zygote has therefore a double structure, for it contains an equal number of chromosomes brought in by the paternal and by the maternal gamete —in the case of a plant by the pollen grain as well as by the ovule .

By a process of re- peated

division the zygote gives rise to a plant (or an animal) whose cells appar- ently retain the double structure throughout . Cer- tain of the cells of such a zygote become the germ cells and are set apart, as it were, for the formation of gametes . Histology has shown that when this occurs -the cells lose the double structure which they had hitherto possessed, and that as the result of a process known as the reduction e division gametes are formed ° in which the number of chromosomes is one half of that which characterizes the cells of the zygote . It is generally acknowledged that the chromosomes play an important part in the hereditary process, and it is possible that the divisions which they undergo in gametogenesis are connected with the observed inheritance of characters . We shall refer later to the few observations which seem to connect the two sets of phenomena . Our conception of what occurs when a cross is made between two individuals may be illustrated by the diagram which forms fig . 2 . Zygotes are here represented by squares and gametes by circles . The dominant and recessive characters are indicatedby small plain and black rectangles . Each zygote must contain two and each gamete but one of these unit-characters . Zygotes such as the original parents which breed true to a given character are said to be homozygous for that character, and from their nature such homozygotes must produce identical gametes . Consequently when a cross is made only one kind of zygote can be formed, viz. that containing both the dominant and recessive unit-characters .

When the germ-cells of such a heterozygote split to

form gametes, these, as indicated in fig . 2, will be of two sorts containing the dominant and recessive characters respectively, and will be produced in equal numbers . If we are dealing with a hermaphrodite plant such as the pea the ovules will consist of one half bearing only the dominant character and one half bearing only the recessive character; and this will be true also of the pollen grains . Consequently each dominant ovule has an equal chance of being fertilized by a dominant or by a recessive pollen grain, and the dominant ovules must therefore give rise to equal numbers of dominant homozygous and of heterozygous plants . Similarly the recessive ovules must give rise to equal numbers of recessive homozygotes and of heterozygotes . Hence of the total offspring of such a plant one quarter will be pure dominants, one quarter recessives, and one half heterozygotes as indicated in fig . 2 . Where one character is completely dominant over the other, heterozygotes will be indistinguishable in appearance from the homozygous dominant, and the Fs generation will be composed of three plants of the dominant form to each recessive . These are the proportions actually found by Mendel in the pea and by many other more recent observers in a number of plants and animals . The experimental facts are in accordance with the conception of unit characters and their transmission from zygote to gamete in the way outlined above; and the numerical results of breeding experiments are to be regarded as proving that in the formation of gametes from the heterozygote the unit-characters are treated as unblending entities separating cleanly, or segregating, from one another . From this it follows that any gamete can carry but one of a pair of unit-characters and must therefore be pure for that character . The principle of the segregation of characters in gametogenesis with its natural corollary, the purity of the gametes, is the essential part of Mendel's discoveries .

The quite distinct phenomenon of dominance observed by him in Pisum occurs in many other cases, but, as will appear below, is by no means universal . Illustrations.—Mendelian inheritance in its simplest form, i.e. for a single pair of characters, has already been shown to occur in many species of animals and plants, and for many very diverse characters . In some cases

complete dominance of one of the pair of unit-characters occurs; in others the form of heterozygote is more or less intermediate . Fresh cases are continually being recorded and the following short list can but serve to give some idea of the variety of characters in which Mendelian inheritance has been demonstrated . A . Dominance. neatly or quite complete . (The dominant character is given first) . Tall and dwarf habit (pea, sweet pea) . Round seed and wrinkled seed (pea) . Long pollen and round pollen (sweet pea) . Starch and sugar endosperm (maize) . Hoariness and absence of hairs (stocks, Lychnis) .

Beardless and bearded

condition (wheat) . Prickliness and smoothness of fruits (Datura) . Palm and fern leaf (Primula) . Purple and red flowers (sweet pea, stocks, &c.) . Fertility and sterility of anthers (sweet pea) . Susceptibility and immunity to rust (wheat) . Rose comb and single comb (fowls) . Black and white plumage (Rosecomb bantams) . Grey and black coat colour (rabbits, mice) . Bay and chestnut coat colour (horses) . Pigmentation and albinism (rabbits, rats, mice) . Polled and horned condition (cattle) .

Short and long "

Angora " coat (rabbits) . Normal and waltzing habit (mice) . Deformed hand with but two phalanges in digits and normal hand (man) . ----------------i T [X] [T] T T [-II LT . D Parents .0 Ft Zygote / \ ' Fa Zygotst FIG . 2 . B . Absence of dominance, the heterozygote being more or less intermediate in form . Black and white splashed plumage (Andalusian fowls) . Lax and dense ears (wheat) . Six rowed and two rowed ears (barley) . Dominance.—The meaning of this phenomenon is at present obscure, and we can make no suggestion as to why it should be complete in one case, partial in another, and entirely absent in a third .

When found it is as a

rule definite and orderly, but there are cases known where irregularity exists . The extra toe characteristic of certain breeds of fowls, such as Dorkings, behaves generally as a dominant character, but in certain cases it has been ascertained that a.fowl without an extra toe may yet carry the extra toe character . It is possible that in 1lli some cases dominance may be conditioned by the presence of other features, and certain crosses in sheep lend colour to the supposition that sex may be such a feature . A cross between the polled Suffolk and the horned Dorset breeds results in horned rams and polled ewes only, though in the F2 generation both sexes appear with and without horns . At present the simplest hypothesis which fits the facts is that horns are dominant in the male and recessive in the female . It is important not to confuse cases of apparent reversal of dominance such as the above with cases in which a given visible character may be the result of two entirely different causes . One white hen may give only colour chicks by a coloured cock, whilst the same cock with another white hen, indistinguishable in appearance from the former, will give only white chickens containing a few dark ticks . There is here no reversal of dominance, but, as has been abundantly proved by experiment, there are two entirely distinct classes of white fowls, of which one is dominant and the other recessive to colour . The Presence and Absence Hypothesis.—Whether the phenomenon of dominance occur or not, the unit-characters exist in pairs, of which the members are seemingly interchangeable . In virtue of this behaviour the unit-characters forming such a pair have been termed allelomorphic to one another, and the question arises as to what is the nature of the relation between two allelomorphs . The fact that such cases of heredity as have been fully worked out can all be formulated in terms of allelomorphic pairs is suggestive, and has led to what may be called the " presence and absence " hypothesis . An allelomorphic pair represents the only two possible states of any given unit-character in its relation to the gamete, viz. its presence or its absence .

When the unit-character is present the quality for which it stands is manifested in the zygote: when it is absent some other quality previously concealed is able to appear . When the unit-character for yellowness is present in a pea the seeds are yellow, when it is absent the seeds are

green . The green character is underlying in all yellow seeds, but can only appear in the absence of the unit-character for yellowness, and greenness is allelomorphic to yellowness because it is the expression of absence of yellowness . Dihybridism.—The instances hitherto considered are all simple cases in which the individuals crossed differ only in one pair of unit-characters . Mendel himself worked out cases in which the parents differed in more than one allelomorphic pair, and he pointed out that the principles involved were capable of indefinite extension . The inheritance of the various allelomorphic pairs is to be regarded as entirely independent . For example, when two individuals AA and aa are crossed the composition of the F2 generation must be AA + 2Aa +aa . If we suppose that the two parents differ also in the allelomorphic pair B–b, the composition of the F2 generation for this pair will be BB + 2Bb + bb . Hence of the zygotes which are homozygous for AA one quarter will carry also BB, one quarter bb, and one half Bb . And similarly for the zygotes which carry Aa or aa . The various combinations possible together with the relative frequencies of their occurrence may be gathered from fig . 3 .

Of the 16 zygotes there are: 9 containing A and B 3 containing B but not A 3 „ A but not B If neither A nor B In a case of dihybridism the Fl zygote must be heterozygous for the two allelomorphic pairs, i.e. must be of the constitution Aa Bb . It is obvious that such a result may be produced in two ways, either by the union of two gametes, Ab and aB, or of two gametes AB and ab . In the former case each parent must be homozygous for one dominant and one recessive character; in the latter case one parent must be homozygous for both the dominant and the other for both recessive characters . The results of a cross involving. dihybridism may be complicated in several ways by the reaction upon one another of the unit-characters belonging to the

separate allelomorphic pairs, and it will be convenient to consider the various possibilities apart . r . The simplest case is that in which the two allelomorphic pairs affect entirely distinct characters . In the pea tallness is dominant to dwarfness and yellow seeds are dominant to green . . When a yellow tall is crossed with a green dwarf the Fl generation consists entirely of tall yellows . Precisely the same result is obtained by crossing a tall green with a dwarf yellow . In either case all the four characters involved are visible in one or other of the parents . Of every i6 plants produced by the tall yellow Fl, co are tall yellows, 3 are tall greens, 3 are dwarf yellows, and r is a dwarf green . If we denote the tall and dwarf characters by A and a, and the yellow WALNUT FIG.4 .

SI IV OL.E The four types of comb referred to in the

text are shown here . All the drawings were made from male birds . . In the hens the combs are smaller . All four types of comb are liable to a certain amount of minor variation, and the walnut especially so . The presence of minute bristles on its posterior portion, however, serves at once to distinguish it from any other comb . and green seed characters by B and b respectively, then the , constitution of the F2 generation can be readily gathered from fig . 3 . 2 . When the two allelomorphic pairs affect the same structure we may get the phenomenon of novelties appearing in Fl and F2 . Certain breeds of fowls have a " rose " and others a " pea y' comb (fig . 4) . On crossing the two a " walnut " comb results, and the offspring of such walnuts bred together consist of 9 walnuts, 3 roses, 3 peas, and I single comb in every 16 birds .

This case may be brought into

line with the scheme in fig . 3 if we consider the allelomorphic pairs concerned to AA AA Aa As .. BB Bb BB Bb SB bb bB bb aA aA as as BB Bb BB Bb bB b b bb bB b P E A be rose (A) and absence of rose (a), and pea (B) and absence of pea (b) . The zygotic constitution of a rose is therefore AAbb, and of a pea aaBB . A zygote containing both rose and pea is a walnut: a zygote containing neither rose nor pea is a single . The peculiar feature of such a case lies in the fact that absence of rose and absence of pea are the same thing, i.e. single; and this is doubtless owing to the fact that the characters rose and pea both affect the same structure, the comb . 3 . Cases exist in which the characters due to one allelomorphic pair can only become manifest in the presence of a particular member of the other pair . If in fig . 3 the characters due to B–b can only manifest themselves in the presence of A, it is obvious that this can happen in twelve cases out of sixteen, but not in the remaining four, which are homozygous for aa . An example of this is to be found in the inheritance of coat colour in rabbits, rats and mice where the allelomorphic pairs concerned are wild grey colour (B) dominant to black (b) and pigmentation (A) dominant to albinism (a) . Certain albinos (aaBB) crossed with blacks (AAbb) give only greys (AaBb), and when these are bred together they give 9 greys, 3 blacks and 4 albinos .

Of the 4 albinos 3 carry the grey character and r does not, but in the absence of the pigmentation

factor (A) this is not visible . The ratio 9 : 3 : 4 must be regarded as a 9 : 3 : 3 : I ratio, in which the last two terms are visibly indistinguishable owing to the impossibility of telling by the eye whether an albino carries the character for grey' or not . 4 . The appearance of a zygotic character may depend upon the coexistence in the zygote of two unit-characters belonging to different allelomorphic pairs . If in the scheme shown in fig . 3 the manifestation of a given character depends upon the simultaneous presence of A and B, it is obvious that 9 of the 16 zygotes will present this character, whilst the remaining 7 will be without it . This is shown graphically in fig . 5, where the 9 squares have been shaded and the 7 left plain . The sweet pea offers an example of this phenomenon . White sweet peas breed true to whiteness, but when certain strains of whites are crossed the offspring are all coloured .. In the next generation (F2) these F1 plants give rise to 9 coloured and 7 whites in every 16 plants . Colour here is a compound character whose manifestation depends upon the co-existence of two factors in the zygote, and each of the original parents was homozygous for one of the two factors necessary to the production of colour .

The ratio 9 : 7 is in reality a 9 : 3 : 3 : I ratio in which, owing to

special conditions,- the zygotes represented by the last three terms are indistinguishable from one another by the eye . The phenomena of dihybridism, as illustrated by the four examples given above, have been worked out in many other cases for plants and animals . Emphasis must be laid upon the fact that, although the unit-characters belonging to two pairs may react upon one another in the zygote and affect its character, their inheritance is yet entirely independent . Neither grey nor black can appear in the rabbit unless the pigmentation factor is also present; nevertheless, gametic segregation of this pair of characters takes place in the normal way among albino rabbits, though its effects are never visible until a suitable cross is made . In cases of trihybridism the Mendelian ratio for the forms appearing in F2 is 27 : 9 :.9 : 9: 3 : 3 : 3 : I, i.e . 27 showing dominance of three characters, three groups of 9 each showing dominance of two characters, three groups of 3 each showing dominance of one character, and a single individual out of 64 which is homozygous for all three recessive characters . It is obvious that the system can be indefinitely extended to embrace any number of allelomorphic pairs . Reversion.—Facts such as those just dealt with in connexion with certain cases of dihybridism throw an entirely new light upon the phenomenon known as reversion on crossing . This is now seen to consist in the meeting of factors which had in some way or other become separated in phylogeny . The albino rabbit when crossed with the black " reverts " to the wild grey colour, because each parent supplies one of the two factors upon which the manifestation of the wild colour depends . So also the wild purple sweet pea may come as a reversion on crossing two whites . In such cases the reversion appears in the Ft generation, because the two factors upon which it depends are the dominants of their respective allelomorphic pairs .

Where the reversion depends upon the simultaneous absence of two characters it cannot appear until the F2 generation . When fowls with rose and pea combs are crossed the reversionary single comb characteristic of the wild

Gallus bankiva first appears in the F2 generation . Gametic Coupling.—In certain cases the distribution of characters in heredity is complicated by the fact that particular unit-characters tend to become associated or coupled together during gametogenesis . In no case have we yet a complete explanation of the phenomenon, but in view of the important bearing which these facts must eventually have on our ideas of the gametogenic process an illustration may be given . The case in which two white sweet peas gave a coloured on crossing has already been described, and it was seen that the production of colour was dependent upon the meeting of two factors, of which one was brought in by each parent . If the allelomorphic pairs be denoted by C–c and R–r, then the zygotic constitution of the two parents must have been CCrr and ccRR respectively . The F1 plant may be either purple or red, two characters which form an allelomorphic pair in which the former is dominant, and which may be denoted by the letters B–b . If B is brought in by one parent only the F1 plant will be heterozygous for all three allelomorphic pairs, and therefore of the constitution Cc Rr Bb . In the F2 generation the ratio of coloured to white must be 9 : 7, and of purple to red 3 I; and experiment has shown that this generation is composed on the average of 27 purples, 9 reds and 28 whites out of every 64 plants . The exact composition of such a family may be gathered from the accompanying table (fig . 6) . So far the case is perfectly smooth, and it is only on the introduction of another character that the phenomenon of partial coupling is witnessed .

Two kinds of pollen grain occur in the sweet pea . In some plants they are oblong in shape, whilst in others they are round, the latter condition being recessive to the former . If the original white parents were homozygous for long and round respectively the Fl purple must be heterozygous, and in the F2 generation, as experiment has shown, the ratio of longs to rounds for the whole family is 3 : I . But among the purples there are about twelve longs to each round, the excess of longs here being balanced by the reds, where the proportion is t long to about 3.5 rounds . There is partial coupling of long pollen with the purple colour and a complementary coupling of the red colour with round pollen . This result would be brought about if it were supposed that seven out of every eight purple gametes produced by the Fl plant carried the long pollen character, and that seven out of every eight red gametes carried the round pollen character . The facts observed

fit in with the supposition that the gametes are produced in series of sixteen, but how such result could be brought about is a question which for the present must remain open . Spurious Allelomorphism.—Instances of association between characters are known in which the connection is between the dominant member of one pair and the recessive of another . In many sweet peas the standard folds over towards the wings, and the flower is said to be hooded . This " hooding " behaves as a recessive towards the erect standard . Red sap colour is also recessive to purple . In families where purples and reds as well as erect and hooded standards occur it has been found, as might be expected, that erect standards are to hooded ones, and that purples are to reds as 3:1 .

Were the case one of simple dihybridism the F2 generation should be composed of q erect purples, 3 hooded purples, 3 erect reds and i hooded red in every 16 . Actually it is composed of 8 erect purples, 4 hooded purples and 4 erect reds . The

hood will not associate with the red, but occurs only on the purples . Cases like this are best interpreted on the assumption that during gametogenesis there is some form of repulsion between the members of the different pairs—in the present instance between the factor for purple and that for the erect standard—so that all the gametes which contain the purple factor are free from the factor for the erect standard . To the process involved in this assumption the term spurious allelomorphism has been applied . Sex.—On the existing evidence it is probable that the inheritance of sex runs upon the same determinate lines as that of other characters . Indeed, there occurs in the sweet pea what may be regarded as an instance of sex inheritance of the simplest kind . Most sweet peas are hermaphrodite, but some are found in which the anthers are sterile and the plants function only as females . This latter condition is recessive to the hermaphrodite one and segregates from it in the ordinary way . Most cases of sex inheritance, however, are complicated, and it is further possible that the phenomena may be of a different order in plants and animals . Instructive in this connexion are certain cases in which one of the characters of an allelomorphic pair may be coupled with a particular sex . The pale lacticolor variety of the currant moth (Abraxas grossulariata) is recessive to, the normal form, and in families produced by heterozygous parents one quarter of the offspring are of the variety .

Though the sexes occur in approximately equal numbers, all the lacticolor its such families are females; and the association of sex with a character exhibiting normal segregation is strongly suggestive of a similar process obtaining for sex also .

Castle has worked out similar cases in other Lepidoptera and has put forward an hypothesis of sex inheritance on the basis of the Mendelian segregation of sex determinants . An ovum or spermatozoon can carry either the male or the female character, but it is essential to Castle's hypothesis that a male spermatozoon should fertilize only a female ovum and vice versa, and consequently on his view all zygotes are heterozygous in respect of sex . Whether any such gametic selection as that postulated by Castle occurs here or elsewhere must for the present remain unanswered . Little evidence exists for it at present, but the possibility of its occurrence should not be ignored . More recently evidence has been brought forward by Bateson and others (3) which supports the view that the inheritance of sex is on Mendelian lines . The analysis of cases where there is a closer association between a Mendelian character and a particular sex has 'suggested that femaleness is here dominant to maleness, and that the latter sex is homozygous while the former is heterozygous . Chromosomes and Unit-Characters.—Breeding experiments have established the conception of definite unit-characters existing in the cells of an organism: in the cell histology has demonstrated the existence of small definite bodies—the chromosomes . During gametogenesis there takes place what many histologists regard as a differentiating division of the chromosomes: at the same period occurs the segregation of the unit-characters . Is there a relation between the postulated unit-character and the visible chromosome, and if so what is this relation ? The researches of E . B .

Wilson and others have shown that in certain Hemiptera the character of sex is definitely associated with a particular chromosome . The males of Pro-tenor possess thirteen chromosomes, and the qualitative division on gametogenesis results in the production of equal numbers of spermatozoa having six and seven chromosomes . The somatic number of chromosomes in the female is fourteen, and consequently all the mature ova have seven chromosomes . When a spermatozoon with seven chromosomes meets an ovum the resulting zygote has fourteen chromosomes and is a female; when a spermatozoon with six chromosomes meets an ovum the resulting zygote has thirteen chromosomes and is a male . In no other instance has any such definite relation been established, and in many cases at any' rate it is certain that it could not be a simple one . The gametic number of chromosomes in wheat is eight, whereas the work of R . H . Biffen and others has shown that the number of unit-characters in this species is considerably greater . If therefore there exists a definite relation between the two it must be supposed that a chromosome can carry more than a single unit-character . It is not impossible that future work on gametic coupling may throw light upon the matter . Heredity and Variation.—It has long been realized that the problems of heredity and variation are closely interwoven, and that whatever throws light upon the one may be expected to illuminate the other . Recent as has been the rise of the study of genetics, it has, nevertheless, profoundly influenced our views as to the nature of these phenomena .

Heredity we now perceive to be a method of analysis, and the facts of heredity constitute a series of reactions which enable us to argue towards the constitution of living matter . And essential to any method of analysis is the recognition of the individuality of the individual . Constitutional

differences of a radical nature may be concealed beneath apparent identity of external form . Purple sweet peas from the same pod, indistinguishable in appearance and of identical ancestry, may yet be fundamentally different in their constitution . From one may come purples, reds and whites, from another only purples and reds, from another purples and whites alone, whilst a fourth will breed true to purple . Any method of investigation which fails to take account of the radical differences in constitution which may underlie external similarity must necessarily be doomed to failure . Conversely, we realize to-day that individuals identical in constitution may yet have an entirely different ancestral history . From the cross between two fowls with rose and pea combs, each of irreproachable pedigree for generations, come single combs in the second generation, and these singles are precisely similar in their behaviour to singles bred from strains of unblemished ancestry . In the ancestry of the one is to be found no single over a long series of years, in the ancestry of the other nothing but singles occurred . The creature of given constitution may often be built up in many ways, but once formed it will behave like others of the same constittt tion . The one sure test of the constitution of a living thing lies in the nature of the gametes which it carries, and it is the analysis of these gametes which forms the province of heredity . The clear cut and definite mode of transmission of characters first revealed by Mendel leads inevitably to the conception of a definite and clear-cut basis for those characters .

Upon this structural basis, the unit-character, are grounded certain of the phenomena now termed variation . Varieties exist as such in virtue of differing in one or more unit-characters from what is conventionally termed the type; and since these unit- MENDELSSOHN,

MOSES (1729-1786), Jewish philosopher, was born in Dessau in 1729 . His father's name was Mendel, and he was later on surnamed Mendelssohn (=son of Mendel) . He was the foremost Jewish figure of the 18th century, and to him is attributable the renaissance of the House of Israel . With this third Moses (the other two being the Biblical lawgiver and Moses Maimonides) a new era opens in the history of the Jewish people . Mendel Dessau was a poor scribe—a writer of scrolls—and his son Moses in his boyhood developed curvature of the spine . His early education was cared for by his father and by the local rabbi, David Frankel . The latter, besides teaching him the Bible and Talmud, introduced to him the philosophy of Maimonides (q.v.) . Frankel received a call to Berlin in 1743 . Not many months later a weakly lad knocked at one of the gates of Berlin . He was admitted after an altercation, and found a warm welcome at the hands of his former teacher . His life at this period was a struggle against crushing poverty, but his scholarly ambition was never relaxed .

A refugee

Pole, Zamosz, taught him mathematics, and a young Jewish physician was his tutor in Latin . He was, however, mainly self-taught . " He learned to spell and to philosophize at the same time" (Graetz) . With his scanty earnings he bought a Latin copy of Locke's Essay concerning the Human Understanding, and mastered it with the aid of a Latin dictionary . He then made the acquaintance of Aaron Solomon Gumperz, who taught him the elements of French and English . In 1750 he was appointed by a wealthy silk-merchant, Isaac Bernhard, as teacher to his children . Mendelssohn soon won the confidence of Bernhard, who made the young student successively his book-keeper and his partner . Gumperz or Hess rendered a conspicuous service to Mendelssohn and to the cause of enlightenment in 1754 by introducing him to Lessing . Just as the latter afterwards makes Nathan the Wise and Saladin meet over the chess-board, so did Lessing and Mendelssohn actually come together as lovers of the game . The Berlin of the day—the day of Frederick the Great—was in a moral and intellectual ferment . Lessing was the great liberator of the German mind . He had already begun his work of toleration, for he had recently produced a drama (Die Juden, 1749), the motive of which was to prove that a Jew can be possessed of nobility of character .

This notion was being generally ridiculed as untrue, when Lessing found in Mendelssohn the realization of his

dream . Within a few months of the same age, the two became brothers in intellectual and artistic cameraderie . Mendelssohn owed his first introduction to the public to Lessing's admiration . The former had written in lucid German an attack on the national negle,ct of native philosophers (principally Leibnitz.), and lent the manuscript to Lessing . Without consulting the author, Lessing published anonymously Mendelssohn's Philosophical Conversations (Philosophische Gesprache) in 1755 . In the same year there appeared in Danzig an anonymous satire, Pope a Metaphysician (Pope ein Metaphysiker), the authorship of which soon transpired . It was the joint work of Lessing and Mendelssohn . From this time Mendelssohn's career was one of ever-increasing brilliance . He became (1756-1759) the leading spirit of Nicolai's important literary undertakings, the Bibliothek and the Literaturbriefe, and ran some risk (which Frederick's good nature obviated) by somewhat freely criticizing the poems of the king of Prussia . In 1762 he married . His wife was Fromet Gugenheim, who survived him by twenty-six years . In the year following his marriage Mendelssohn won the prize offered by the Berlin Academy for an essay on the application of mathematical proofs to metaphysics, although among the competitors were Abbt and Kant .

In

October 1763 the king granted Mendelssohn the privilege of Protected Jew (Schutz-Jude)--which assured his right to undisturbed residence in Berlin . As a result of his correspondence with Abbt, Mendelssohn resolved to write on the Immortality of the Soul . Materialistic views were at the time rampant and fashionable, and faith in immortality was at a low ebb . At this favourable juncture appeared the Phddon (1767) . Modelled on Plato's dialogue characters must from their behaviour in transmission be regarded as discontinuous in their nature, it follows that the variation must be discontinuous also . A present tendency of thought is to regard the discontinuous variation or mutation as the material upon which natural selection works, and to consider that the process of evolution takes place by definite steps . Darwin's opposition to this view rested partly upon the idea that the discontinuous variation or sport would, from the rarity of its occurrence, be unable to maintain itself against the swamping effects of intercrossing with the normal form . Mendel's work has shown that this objection is not valid, and the precision of the mode of inheritance of the discontinuous variation leads us to inquire if the small or fluctuating variation can be shown to have an equally definite physiological basis before it is admitted to play any part in the production of species . Until this has been shown it is possible to consider the discontinuous variation as the unit in all evolutionary change, and to regard the fluctuating variation as the uninherited effect of environmental accident . The Human Aspect.—In conclusion we may briefly allude to certain practical aspects of Mendel's discovery . Increased knowledge of heredity means increased power of control over the living thing, and as we come to understand more and more the architecture of the plant or animal we realize what can and what cannot be done towards modification or improvement . The experiments of Biffen on the cereals have demonstrated what may be done with our present knowledge in establishing new, stable and more profitable varieties of wheat and barley, and it is impossible to doubt that as this knowledge becomes more widely disseminated it will lead to considerable improvements in the methods of breeding animals and plants .

It is not, however, in the economic

field, important as this may be, that Mendel's discovery is likely to have most meaning for us: rather it is in the new light in which man will come to view himself and his fellow creatures . To-day we are almost entirely ignorant of the unit-characters that go to make the difference between one man and another . A few diseases, such as alcaptonuria and congenital cataract, a digital malformation, and probably eye colour, are as yet the only cases in which inheritance has been shown tp run upon Mendelian lines . The complexity of the subject must render investigation at once difficult and slow; but the little that we know to-day offers the hope of a great extension in our knowledge at no very distant time . If this hope is borne out, if it is shown that the qualities of man, his body and his intellect, his immunities and his diseases, even his very virtues and vices, are dependent upon the ascertainable presence or absence of definite unit-characters whose mode of transmission follows fixed laws, and if also man decides that his life shall be ordered in the light of this knowledge, it is obvious that the social system will have to undergo considerable changes . (i) W . Bateson, Mendel's Principles of Heredity (Cambridge, 1902), contains translation of Mendel's paper . (2) W . Bateson, An Address on Mendelian Heredity and its Application to Man, " Brain," pt. exiv . (1906) . (3) W . Bateson, Mendel's Principles of Heredity (1909) .

(4¢) R . H . Biffen, " Mendel's Laws of Inheritance and Wheat Breedings," Journ . Agr .

Soc., vol. i . (1905) (5) W . E . Castle, " The Heredity of Sex," Bull . Mus . Comp . Zool . (Harvard, 1903) .

(6) L . Cuenot, " L'H6r6dit6 de la pigmentation chef

les souris," Arch . Zool . Exp . (19o3-19o4) . (7) H. de Vries, Die Mutationstheorie (Leipzig, 1901-1903) . (8) L . Doncaster and G . H . Raynor, " Breeding Experiments with Lepidoptera," Proc . Zool . Soc .

(

London, 1906) . (9) C . C . Hurst, " Experimental Studies on Heredity in Rabbits," Journ . Linn . Soc . (1905) . (to) G . J . Mendel, Versuche giber Pflanzen-Hybriden, Verh. natur. f. ver. in Brunn, Bd . IV . (1865) .

(u) Reports to the Evolution

Committee of the Royal Society, vols. i.-iii . (London, 1902-1906, experiments by W . Bateson, E . R . Saunders, R . C . Punnett, C . C . Hurst and others) . (12) E . B . Wilson, " Studies in Chromosomes," vols. i.-iii .

Journ . Exp . Zool . (1905-1906) . (13) T . B .

Wood, " Note on the Inheritance of Horns and Fare Colour in Sheep," Journ . Agr . Soc. vol. i . (Nos) . (R . C .

P.) So far, Mendelssohn had devoted his talents to philosophy and

criticism; now, however, an incident turned the current, of his life in the direction of the cause of Judaism . Lavater was one of the most ardent admirers of Mendelssohn . He described him as " a companionable, brilliant soul, with piercing eyes, the body of an Aesop—a man of keen insight, exquisite taste and wide erudition . frank and open-hearted." Lavater was fired with the ambition to convert his friend to Christianity . In the preface to a German translation of Bonnet's essay on Christian Evidences, Lavater publicly challenged Mendelssohn to refute Bonnet or if he could not then to " do what wisdom, the love of truth and honesty must bid him, what a Socrates would have done if he had read the book and found it unanswerable." This appeal produced a painful impression . Bonnet resented Lavater's action, but Mendelssohn was bound to reply, though opposed to religious controversy . As he put it: " Suppose there were living among my contemporaries a Confucius or a Solon, I could, according to the principles of my faith, love and admire the great man without falling into the ridiculous idea that I must convert a Solon or a Confucius." Here we see the germs of Mendelssohn's Pragmatism, to use the now current term . He shared this with Lessing; in this case, at all events, it is probable that the latter was indebted to Mendelssohn . But before discussing this matter, we must follow out the consequences of Lavater's intrusion into Mendelssohn's affairs . The latter resolved to devote the rest of his life to the emancipation of the Jews . Among them secular studies had been neglected, and Mendelssohn saw that he could best remedy the defect by attacking it on the religious side . A great chapter in the history of culture is filled by the influence of translations of the Bible . Mendelssohn added a new section to this chapter by his German translation of the Pentateuch and other parts of the Bible .

This work (1783) constituted Mendelssohn the

Luther of the German Jews . From it, the Jews learned the German language; from it they imbibed culture; with it there was born a new desire for German nationality; as a result of its popularity was inaugurated a new system of Jewish education . Some of the conservatives among the Jews opposed these innovations, but the current of progress was too strong for them . Mendelssohn was the first great champion of Jewish emancipation in the 18th century . He it was who induced C . W . Dohm to publish in 1781 his epoch-making work, On the Civil Amelioration of the Condition of the Jews, a memorial which played a great part in the triumph of tolerance . Mendelssohn himself pgblished a German translation of the Vindiciae judaeorum by Menasseh ben Israel . The excitement caused by these proceedings led Mendelssohn to publish his most important contribution to the problems connected with the position of Judaism in relation to the general life . This work was the Jerusalem (1783; Eng. trans . 1838 and 1852) . It is a forcible plea for freedom of conscience .

Kant described it as " an irrefutable book." Its basic idea is that the

state had no right to interfere with the religion of its citizens . As Kant put it, this was " the proclamation of a great reform, which, however, will be slow in manifestation and in progress, and which will affect not only your people but others as well." Mendelssohn asserted the pragmatic principle of the possible plurality of truths: that just as various nations need different constitutions—to one a monarchy, to another a republic, may be the most congenial to the national genius—so individuals may need different religions . The test of religion is its effect on conduct . This is the moral of Lessing's Nathan the Wise, the hero of which is undoubtedly Mendelssohn . The parable of the three rings is the epitome of the pragmatic position . One direct result of this pragmatism was unexpected . Having been taught that there is no absolutely true religion, Mendelssohn's own descendants—a brilliant circle, of which the musician Felix was the most noted—left the Synagogue for the Church . But despite this, Mendelssohn's theory was found to be a strengthening bond in Judaism . For he maintained that Judaism was less a " divine need, than a revealed life." In the first part of the 19th century, the criticism of Jewish dogmas and traditions was associated with a firm adhesion to the older Jewish mode of living . Reason was applied to beliefs, the historic consciousness to life . Modern reform in Judaism is parting to some extent from this conception, but it still holds good even among the liberals . Of Mendelssohn's remaining years it must suffice to say that he progressed in fame numbering among his friends more and more of the greatest men of the age .

His Morgenstunden appeared in 1785, and he died as the result of a

cold contracted while carrying to his publishers in 1786 the manuscript of a vindication of his friend Lessing, who had predeceased him by five years . Mendelssohn had six children . His sons were: Joseph (founder of the Mendelssohn banking house, and a friend and benefactor of Alexander Humboldt), whose son Alexander (d . 1871) was the last Jewish descendant of the philosopher; Abraham (who married Leah Bartholdy and was the father of Fanny Hensel and J . L . Felix Mendelssohn-Bartholdy); and Nathan (a mechanical engineer of considerable repute) . His daughters were Dorothea, Recha and Henriette, all brilliantly gifted women . MENDELSSOHN-BARTHOLDY, JAKOB LUDWIG FELIX (1809-1847), German composer, grandson of Moses Mendelssohn (q.v.), was born in Hamburg on the 3rd of February 1809 . In consequence of the troubles caused by the French occupation of Hamburg, Abraham Mendelssohn, his father, migrated in 1811 to Berlin, where his grandmother Fromet, then in the twenty-fifth year of her widowhood, received the whole family into her house, No . 7 Neue Promenade . Here Felix and his sister Fanny received their first instruction in music from their mother, under whose care they progressed so rapidly that their exceptional talent soon became apparent . Their next teacher was Madame Bigot, who, during the temporary residence of the family in Paris in 1816, gave them valuable instruction .

On their return to Berlin they took lessons in thoroughbass and composition from Zelter, in

pianoforte-playing from Ludwig Berger, and in violin-playing from Henning—the care of their general education being entrusted to the father of the novelist Paul Heyse . Felix first played in public on the 24th of October 1818, taking the pianoforte part in a trio by Woelfl . On the 1th of April 1819 he entered the Berlin Singakademie as an alto, and in the following year began to compose with extraordinary rapidity . His earliest dated work is a cantata, In K4/trend feierlichen Tonen, completed on the 13th of January 1820 . During that year alone he produced nearly sixty movements, including songs, pianoforte sonatas, a trio for pianoforte, violin and violoncello, a sonata for violin and pianoforte, pieces for the organ, and even a little dramatic piece in three scenes . In 1821 he wrote five symphonies for stringed instruments, each in three movements; motets for four voices, an MENDELSSOHN-BARTHOLDY L21 opera, in one act, called Soldatenliebschaft; another, called Die beiden Padagogen; part of a third, called Die wandernden Comodianten; and an immense quantity of other music of different kinds, all showing the precocity of his genius . The original autograph copies of these early productions are preserved in the Berlin Library, where they form part of a collection which fills forty-four large volumes, all written with infinite neatness, and for the most part carefully dated—a sufficient proof that the methodical habits which distinguished his later life were formed in early childhood . In 1821 Mendelssohn paid his first visit to Goethe, with whom he spent sixteen days at Weimar, in company with Zelter . From this year also dates his first acquaintance with Weber, who was then in Berlin superintending the production of Der Freischut,z; and from the summer of 1822 his introduction, at Cassel, to another of the greatest of his contemporaries, Ludwig Spohr . During this year his pen was even more prolific, producing, among other works, an opera, in three acts, entitled Die beiden Neff en, oder der Onkel aus Boston, and a pianoforte concerto, which he played in public at a concert given by Frau Anna Milder . It had long been a custom with the Mendelssohn family to give musical performances on alternate Sunday mornings in their dining-room, with a small orchestra, which Felix always conducted, even when he was not tall enough to be seen without standing upon a stool . For each of these occasions he produced some new work—playing the pianoforte pieces himself, or entrusting them to Fanny, while his sister Rebecka sang, and his brother Paul played the violoncello .

In this way Die beiden Neffen was first privately performed, on-the fifteenth anniversary of his birthday, the 3rd of February 1824 . Between the 3rd and the 31st of

March in this year he composed his fine symphony in C minor, now known as Op . 10, and soon afterwards the quartet in B minor, Op . 3, and the (posthumous) pianoforte sestet, Op. rio . In this year also began his lifelong friendship with Moscheles, who, when asked to receive him as a pupil, said, " If he wishes to take a hint from me, as to anything new to him, he can easily do so; but he stands in no need of lessons." In 1825 Abraham Mendelssohn took Felix to Paris, where among other musicians then resident in the French capital he met the two most popular dramatic composers of the age, Rossini and Meyerbeer, and lived on terms of intimacy with Hummel, Kalkbrenner, Rode, Baillot, Herz, and many other artists of European celebrity . On this occasion also he made his first acquaintance with Cherubini, who, though he rarely praised any one, expressed a high opinion of his talent, and recommended him to write a Kyrie, for five voices, with full orchestral accompaniments, which he himself described as " exceeding in thickness " anything he had attempted . From letters written at this period we Learn that Felix's estimate of the French school of music was far from flattering; but he formed some friendships in Paris, which were renewed on later occasions . He returned to Berlin with his father in May 1825, taking leave of his Parisian friends on the 19th of the month, and interrupting his journey at Weimar for the purpose of paying a second visit to Goethe, to whom he dedicated his quartet in B minor . On reaching home he must have worked with greater zeal than ever; for on the loth of August in this same year he completed an opera, in two acts, called Die Hochzeit des Camacho, a work of considerable importance . No ordinary boy could have escaped uninjured from the snares attendant upon. such a life as that which Mendelssohn now lived . Notwithstanding his overwhelming passion for music, his general education had been so well cared for that he was able to hold his own, in the society of his seniors, with the grace of an accomplished man of the world . He was already recognized as a leading spirit by the artists with whom he associated, and these artists were men of acknowledged talent and position .

The temptations to

egoism by which he was surrounded would have rendered most clever students intolerable . But the natural amiability of his disposition, and thehealthy influence of his happy home-life, counteracted all tendencies towards self-assertion . Soon after his return from Paris, Abraham Mendelssohn removed from his mother's residence to No . 3 Leipziger Strasse, a roomy, old-fashioned house, containing an excellent music-room, and in the grounds adjoining a " Gartenhaus " capable of accommodating several hundred persons at the Sunday performances.' In the autumn of the following year this " garden-house " witnessed a memorable private performance of the work by means of which the greatness of Mendelssohn's genius was first revealed to the outer world—the overture to Shakespeare's Midsummer Night's Dream . The finished score of this famous composition is dated " Berlin, August 6, 1826 "—its author was only seventeen and a half years old . Yet in no later work does he exhibit more originality of thought, more freshness of conception, or more perfect mastery over the details of technical construction, than in this delightful inspiration . The overture was first publicly performed at Stettin, in February 1827, under the direction of the young composer, who was at once accepted as the leader of a new and highly characteristic manifestation of the spirit of progress . Henceforth we must speak of him, not as a student, but as a mature and experienced artist . Meanwhile Camacho's Wedding had been submitted to Spontini, with a view to its production at the opera . The libretto, founded upon an episode in the history of Don Quixote, was written by Klingemann, and Mendelssohn threw himself into the spirit of the romance with a keen perception of its peculiar humour . The work was put into rehearsal soon after the composer's return from Stettin, produced on the 29th of April 1827, -and received with great apparent enthusiasm; but a cabal was formed against it, and it never reached a second performance . The critics abused it mercilessly; yet it exhibits merits of a very high order .

The

solemn passage for the trombones, which heralds the first appearance of the knight of La Mancha, is conceived in a spirit of reverent appreciation of the idea of Cervantes, which would have done honour to a composer of lifelong experience . Mendelssohn was annoyed at this injustice, and some time elapsed before his mind recovered its usual bright tone; but he continued to work diligently . Among other serious undertakings, he formed a choir for the study of the choral works of Sebastian Bach, then unknown to the public; and, in spite of Zelter's opposition, he succeeded, in 1829, in inducing the Berlin Singakademie to give a public performance of the Passion according to St Matthew, under his direction, with a chorus of between three and four hundred voices . The scheme succeeded beyond his warmest hopes, and proved the means of restoring to the world great compositions which had never been heard since the death of Bach . But the obstructive party were offended; and at this period Mendelssohn was far from popular among the musicians of Berlin . In April 1829 Mendelssohn paid his first visit to London . His reception was enthusiastic . He made his first appearance before an English audience at one of the Philharmonic Society's concerts—then held in the Argyll Rooms—on the 25th of May, conducting his symphony in C minor from the pianoforte, to which he was led by John Cramer . On the 3oth he played Weber's Concertstuck, from memory, a proceeding at that time extremely unusual . At a concert given by Drouet, on the 24th of June, he played Beethoven's pianoforte concerto in E flat, which had never before been heard in the country-and the overture to A Midsummer Night's Dream was also, for the first time, presented to a London audience . - On returning home from the concert, Attwood, then organist of St Paul's Cathedral, left the score of the overture in a hackney coach, whereupon Mendelssohn wrote out another, from memory, without an error . At another concert he played, with Moscheles, his still unpublished concerto in E, for two pianofortes and ' After Mendelssohn's death this house was sold to the Prussian government; and the " Herrenhaus " now stands on the site of the garden-house .

orchestra . After the

close of the London season he started with Klingemann on a tour through Scotland, where he was inspired with the first idea of his overture to The Isles of Fingal, returning to Berlin at the end of November . Except for an accident to his knee, which lamed him for some time, his visit was highly successful and laid the foundation of many friendships and prosperous negotiations . The visit to England formed the first division of a great scheme of travel which his father wished him to extend to all the most important art centres in Europe . After refusing the offer of a professorship at Berlin, he started again, in May 183o, for Italy, pausing on his way at Weimar, where he spent a fortnight with Goethe, and reaching Rome, after many pleasant interruptions, on the 1st of November . No excitement prevented him from devoting a certain time every day to composition; but he lost no opportunity of studying either the countless treasures which form the chief glory of the great city or the manners and customs of modern Romans . He attended, with insatiable curiosity, the services in the Sistine Chapel; and his keen power of observation enabled him to throw much interesting light upon them . His letters on this subject, however, lose much of their value through his incapacity to comprehend the close relation existing between the music of Palestrina and his contemporaries and the ritual of the Roman Church . His Lutheran education kept him in ignorance even of the first principles of ordinary chanting; and it is amusing to find him describing as enormities peculiar to the papal choir customs familiar to every village singer in England, and as closely connected with the structure of the " Anglican chant " as with that of " Gregorian music." Still, though he could not agree in all points with Baini, the greatest ecclesiastical musician then living, he shared his admiration for the Improperia, the Miserere, and the cantus planus of the Lamentationes and the Exultet, the musical beauty of which he could understand, apart from their ritual significance . In passing through Munich on his return in October 1831 he composed and played his pianoforte concerto in G minor, and accepted a commission (never fulfilled) to compose an opera for the Munich theatre . Pausing for a time at Stuttgart, Frankfort and Dusseldorf he arrived in Paris in December, and passed four pleasant months in the renewal of acquaintances formed in 1825, and in close intercourse with Liszt and Chopin . On the 19th of February 1832 the overture to A Midsummer Night's Dream was played at the conservatoire, and many of his other compositions were brought before the public; but he did not escape disappointments with regard to some of them, especially the Reformation symphony, and the visit was brought to a premature close in March by an attack of cholera, from which, however, he rapidly recovered .

On the 23rd of April 1832 he was again in London, where he twice played his G minor concerto at the Philharmonic concerts, gave a performance on the organ at St Paul's, and published his first book of Lieder ohne Worte . He returned to Berlin in

July, and during the winter he gave public performances of his Reformation symphony, his concerto in G minor, and his Walpurgisnacht . In the following spring he paid a third visit to London for the purpose of conducting his Italian symphony, which was played for the first time, by the Phil-harmonic Society, on the 13th of May 1833 . On the 26th of the same month he conducted the performances at the Lower Rhine festival at Dusseldorf with such brilliant effect that he was at once offered, and accepted, the appointment of generalmusic-director to the town, an office which included the management of the music in the principal churches, at the theatre, and at the rooms of two musical associations . Before entering upon his new duties, Mendelssohn paid a fourth visit to London, with his father, returning to Dusseldorf on the 27th of September 1833 . His influence produced an excellent effect upon the church music and in the concert-room; but his relations with the management of the theatre were not altogether pleasant; and it was probably this circumstance which first led him to forsake the cultivation of the opera for that of sacred music . At Dusseldorf he first designed his famous oratorio St Paul, in response to an application from the Cacilien-Verein at Frankfort, composed his overture to Die schone Melusine, and planned some other works of importance . He liked his appointment, and would probably have retained it much longer had he not been invited to undertake the permanent direction of the Gewandhaus concerts at Leipzig, and thus raised to the highest position attainable in the German musical world . To this new sphere of labour he removed in August 1835, opening the first concert at the Gewandhaus, on the 4th of October, with his overture Die Meeresstille, a work possessing great attractions, though by no means on a level with the Midsummer Night's Dream, The Isles of Fingal, or Melusine . Mendelssohn's reception in Leipzig was most enthusiastic; and under their new director the Gewandhaus concerts prospered exceedingly . Meanwhile-St Paul steadily progressed, and was first produced, with triumphant success, at the Lower Rhine festival at Dusseldorf, on the 22nd of May 1836 . On the 3rd of October it was first sung in English, at Liverpool, under the direction of Sir George Smart; and on the 16th of March 1837 Mendelssohn again directed it at Leipzig .

The next great event in Mendelssohn's life was his happy marriage, on the 28th of March 1837, to Cecile

Charlotte Sophie Jeanrenaud . The honeymoon was scarcely over before he was again summoned to England to conduct St Paul, at the Birmingham festival, on the loth of September . During this visit he played on the organ at St Paul's and at Christ Church, Newgate Street, with an effect which exercised a lasting influence upon English organists . It was here also that he first contemplated the production of his second oratorio, Elijah . Passing over the composition of the Lobgesang in 184o, a sixth visit to England in the same year, and his inauguration of a scheme for the erection of a monument to Sebastian Bach, we find Mendelssohn in 1841 recalled to Berlin by the king of Prussia, with the title of Kapellmeister . Though his appointment resulted in the production of Antigone, Oedipus Coloneus, Athalie, the incidental music to the Midsummer Night's Dream, and other great works, it proved an endless source of vexation, and certainly helped to shorten the composer's life . In 1842 he came to England for the seventh time, accompanied by his wife, conducted his Scotch symphony at the Philharmonic, again played the organ at St Peter's, Cornhill, and Christ Church, Newgate Street, and was received with honour by the queen and the prince consort . He did not, however, permit his new engagements to interfere with the direction of the Gewandhaus concerts; and in 1843 he founded in Leipzig the great conservatoire which soon became the best musical college in Europe, opening it on the 3rd of April in the buildings of the Gewandhaus . In 1844 he conducted six of the Phil-harmonic concerts in London, producing his new Midsummer Night's Dream music, and playing Beethoven's pianoforte concerto in G with extraordinary effect . He returned to his duties at Berlin in September, but succeeded in persuading the king to free him from his most onerous engagements . After a brief residence in Franfort, Mendelssohn returned to Leipzig in September 1845, resuming his old duties at the Gewandhaus, and teaching regularly in the conservatoire . Here he remained, with little interruption, during the winter—introducing his friend Jenny Lind, then at the height of her popularity, to the critical frequenters of the Gewandhaus, and steadily working at Elijah, the first performance of wails he conducted at the Birmingham festival, on the 26th of August 1846 .

The reception of this great work was enthusiastic . Unhappily, the excitement attendant upon its production, added to the irritating effect of the worries at Berlin, made a serious inroad upon the composer's

health . On his return to Leipzig he worked on as usual, but it was clear that his health was seriously impaired . In 1847 he visited England for the tenth and last time, to conduct four performances of Elijah at Exeter Hall, on the 16th, 23rd, 28th and 3oth of April, one at Manchester on the loth, and one at Birmingham on the 27th . But the exertion was beyond his strength . He witnessed Jenny Lind's first appearance at Her Majesty's Theatre, on the 4th of May, and left England on the 9th, little anticipating the trial that awaited him in the tidings of the sudden death of his sister Fanny, which reached him only a few days after his arrival in Frankfort . The loss of his mother in 1842 had shaken him much, but the suddenness with which this last intelligence was communicated broke him down . He fell to the ground insensible, and never fully recovered . In June he was so far himself again that he was able to travel, with his family, by short stages, to Interlaken, where he stayed for some time, illustrating the journey by a series of water-colour drawings, but making no attempt at composition for many weeks . He returned to Leipzig in September, bringing with him fragments of Christus, Loreley, and some other unfinished works, taking no part in the concerts, and living in privacy . On the 9th of October he called on Madame Frege, and asked her to sing his latest set of songs . She left the room for lights, and on her return found him in violent pain and almost insensible .

He lingered for four weeks, and on the 4th of November he passed away, in the presence of his wife, his brother, and his three friends, Moscheles, Schleinitz, and

Ferdinand David . A cross marks the site of his grave, in the Alte Dreifaltigkeits Kirchhof, at Berlin . Mendelssohn's title to a place among the great composers of the century is incontestable . His style, though differing little in technical arrangement from that of his classical predecessors, is characterized by a vein of melody peculiarly his own, and easily distinguishable by those who have studied his works, not only from the genuine effusions of contemporary writers, but from the most successful of the servile imitations with which, even during his lifetime, the music-shops were deluged . In less judicious hands the rigid symmetry of his phrasing might, perhaps, have palled upon the ear; but under his skilful management it serves only to impart an additional charm to thoughts which derive their chief beauty from the evident spontaneity of their conception . In this, as in all other matters of a purely technical character, he regarded the accepted laws of art as the medium by which he might most certainly attain the ends dictated by the inspiration of his genius . Though caring nothing for rules, except as means for producing a good effect, he scarcely ever violated them, and was never weary of impressing their value upon the minds of his pupils . His method of counterpoint was modelled in close accordance with that practised by Sebastian Bach . This he used in combination with an elastic development of the sonata-form, similar to that engrafted by Beethoven upon the lines laid down by Haydn . The principles involved in this arrangement were strictly conservative; yet they enabled him, at the very outset of his career, to invent a new style no less original than that of Schubert or Weber, and -no less remarkable as the embodiment of canons already consecrated by classical authority than as a special manifestation of individual genius . It is thus that Mendelssohn stands before us as at the same time a champion of conservatism and an apostle of progress; and it is chiefly by virtue of these two apparently incongruous though really compatible phases of his artistic character that his influence and example availed, for so many years, to hold in check the violence of reactionary opinion which injudicious partisanship afterwards fanned into revolutionary fury . Concerning Mendelssohn's private character there have never been two opinions .

As a man of the world he was more than ordinarily accomplished—brilliant in conversation, and in his lighter moments overflowing with sparkling humour and ready pleasantry, loyal and unselfish in the more serious business of life, and never weary of working for the general good . As a friend he was unvaryingly kind, sympathetic and true . His earnestness as a Christian needs no stronger testimony than that afforded by his own delineation of the character of St Paul; but it is not too much to say that his

heart and life were pure as those of a little child . (W . S . R.) This article has the unique value of being the record of an eminent musical scholar who was an actual pupil of Mendelssohn . No change of reputation can alter the value of such a record of a man whom even his contemporaries knew to be greater than his works . Mendelssohn's aristocratic horror of self-advertisement unfitted him for triumph in a period of revolution; he died, most inopportunely, when his own powers, like Handel's at the same age, were being wasted on pseudo-classical forms; the new art was not yet ripe; and in the early Wagner-Liszt reign of terror his was the first reputation to be assassinated . That of the too modest and gentle " Romantic " pioneer Schumann soon followed; but, as being more difficult to explain away, and more embarrassing to irreverence and conceit, it remains a subject of controversy . Meanwhile Mendelssohn's reputation, except as the composer of a few inexplicably beautiful and original orchestral pieces, has vanished and been replaced by a pure fiction known as the " Mendelssohn tradition " of orchestral conducting . This fiction is traceable to some characteristic remarks made by Wagner on his experiences of English orchestral playing, remarks which, though not very good-natured, do not bear the full construction popularly imputed to them . If Beethoven had come and conducted in England, Mendelssohn's expostulations with careless players would have been met by references to the " Beethoven tradition "; and, if Wagner had shared Mendelssohn's reluctance to. putting on record remarks likely to wound individual, professional and national sensibilities, it might not have been impossible that reproaches against slipshod and mechanical playing might nowadays be met by references to the " Wagner tradition, for Wagner also found himself compelled to concentrate his care on the main items in the overloaded English orchestral programmes, to the detriment of the rest .

Mendelssohn's influence on the early career of

Joachim is, next to his work in the rediscovery of Bach, his greatest bequest to later musical history . Those many profound and sincere admirers to Joachim to whom the name of Mendelssohn calls up only the Widow in Elijah and the weaker Songs without Words, may find the idea strange; but there is no doubt that . Joachim regarded the continuation of a true Mendelssohn tradition as identical with his own efforts to " uphold the dignity of art." (D . F . T.) MENDgS, CATULLE (1841-1909), French poet and man of letters, of Jewish extraction, was born at Bordeaux on the 22nd of May 1841 . He early established himself in Paris, attaining speedy notoriety by the publication in the Revue fantaisiste (1861) of his " Roman d'une nuit," for which he was condemned to a month's imprisonment and a fine of 500 francs . He was allied with the Parnassians from the beginning of the movement, and displayed extraordinary metrical skill in his first volume of poems, Philomela (1863) . In later volumes—Poesies, le" serie (1876), which includes much of his earlier verse, " Soirs moroses," Conies epiques, Philomela, &c; Poesies (7 vols., 1885), a new edition largely augmented; Les Poesies de Catutle Mendes (3 vols., 1892); La Grive des vignes (1895), &c.—his critics have noted that the elegant verse is distinguished rather by dexterous imitation of different writers than by any marked originality . The versatility and fecundity of Mendes's talent is shown in a series of his critical and dramatic writings, and of novels and short stories, in the latter of which he continues the French tradition of the licentious conk . For the theatre he wrote: La Part du roi (1872), a one-act verse comedy; Les Freres d'armes (1873), drama; Justice (1877), in three acts, characterized by a hostile critic as a hymn in praise of suicide; the libretto of a light opera, Le Capitaine Fracasse (1878), founded on Theophile Gautier's novel; La Femme de Tabarin (1887); Medee (1898), in three acts and in verse; La Reine Fiammette (1898), a conk dramatique in six acts and in verse, the scene of which is laid in the Italy of the Renaissance; Le Fils de l' Nolte (1904), the hero of which is Bar-Cochebas; the Syrian pseudo-Messiah, for the music of C . Erlanger; Scarron (1905); Ariane (1906), for the music of Massenet; and Glatigny (1906) . His critical work includes: Richard Wagner (1886); L'Art au theatre (3 vols:, 1896-1900), a series of dramatic criticisms reprinted from newspapers; and a report addressed to the minister of public instruction and of the fine arts on Le Mouvement poetique fran&ais de 186y d 1900 (new ed., 1903), which includes a bibliographical and critical dictionary of the French poets of the 19th century .

Perhaps the most famous of his novels are: Le Roi

vierge (1880) in which he introduces Louis II. of Bavaria and Richard Wagner; La Maisbn de la vielle (1894), and Gog (1897) . He married in 1866 Mlle Judith Gautier, younger daughter of the poet, from whom he was subsequently separated . On the 9th of February 1909, early in the morning, his dead body was discovered in the railway tunnel of Saint Germain . He had left Paris by the midnight train on the 7th, and it is supposed that, thinking he had arrived at the station, he had opened the door of his compartment while still in the tunnel .