See also:

• ALBUMIN, or ALBUMEN (Lat. albus, white)

ALBUMIN, or ALBUMEN (See also:

• LAT

Lat. albus, See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white)  , an organic sub-stance typical of a See also:

• GROUP

group of bodies (albumins or albuminates) of very complicated chemical See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

composition . They are sometimes called the histogenetic bodies or proteids, because they are essential to the See also:

• BUILDING

building up of the See also:

• ANIMAL
• ANIMAL (Lat. animalis, from anima, breath, soul)

animal organism . The See also:

• VEGETABLE

vegetable See also:

• KINGDOM

kingdom is the See also:

• ORIGINAL

original source of albuminous sub-stances, the albumins being found in greatest quantity in the See also:

• SEED (from the root seen in Lat. serere, to sow)

seed . They also occur in the fluids of the living organism . The See also:

• CHEMISTRY
• CHEMISTRY (formerly "chymistry"; Gr. xvµela; for derivation see ALCHEMY)

chemistry of the albumins is one of the most complicated and difficult in the whole domain of organic chemistry . It has attracted the See also:

• ATTENTION (from Lat. ad-tendo, await, expect; the condition of being " stretched " or " tense ")

attention of many workers, and has formed the subject of a huge literature . In this See also:

• FIELD (a word common to many West German languages, cf. Ger. Feld, Dutch veld, possibly cognate with O.E. f olde, the earth, and ultimately with root of the Gr. irAaror, broad)
• FIELD, CYRUS WEST (1819-1892)
• FIELD, DAVID DUDLEY (18o5-1894)
• FIELD, EUGENE (1850-1895)
• FIELD, FREDERICK (18o1—1885)
• FIELD, HENRY MARTYN (1822-1907)
• FIELD, JOHN (1782—1837)
• FIELD, MARSHALL (183 1906)
• FIELD, NATHAN (1587—1633)
• FIELD, STEPHEN JOHNSON (1816-1899)
• FIELD, WILLIAM VENTRIS FIELD, BARON (1813-1907)

field Bechamp, Cohnheim, Albrecht Kossel, and, especially, Emil See also:

• FISCHER
• FISCHER, EMIL (1852– )
• FISCHER, ERNST KUNO BERTHOLD (1824–1907)

Fischer and his pupils have been extremely active . The See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general trend of these researches lies in the study of the decomposition or " breaking down " products of the See also:

• ALBUMIN, or ALBUMEN (Lat. albus, white)

albumin molecules; once these are accurately determined, the See also:

• SYNTHESIS (Gr. a6vOeacs, from avvrcBivac, to put together)

synthesis of an albumin is but a See also:

• MATTER

matter of See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time . Already we have proceeded far in our know-ledge of the decomposition products, and certain See also:

• SIMPLE

simple proteids have been synthesized . The albumins contain in all cases the elements See also:

• CARBON (symbol C, atomic weight 12)

carbon, See also:

• HYDROGEN [symbol H, atomic weight x-oo8 (0=16)]

hydrogen, See also:

• NITROGEN [symbol N., atomic weight 14.01, 0=16]

nitrogen, See also:

• SULPHUR

sulphur and See also:

• OXYGEN (symbol 0, atomic weight 16)

oxygen; their composition, however, varies within certain limits: C=50-55 %, H=6•9-7.3%,N=15-19%,S=0•3-2.4%,0=19-24%, crystallized albumin is C=51.48 %, H=6.76 %, N= 18.14%, S= o.96 %, 0= 22.66 %, which points to the See also:

• FORMULA
• FORMULA (Lat. diminutive of forma, shape, pattern, &c., especially used of rules of judicial procedure)

formula C72oHnsuN2isS50sas, corresponding to the molecular See also:

• WEIGHT

weight 16,954 . A high molecular weight characterizes these substances, but so far no definite value has been determined by either See also:

• PHYSICAL

physical or chemical means; A . P .

Sabanezhev obtained the value 15,000 by See also:

• RAOULT, FRANCOIS MARIE (1830-1901)

Raoult's method for purified See also:

• EGG (O.E. aeg, cf. Ger. Ei, Swed. aegg, and prob. Gr. u,ov, Lat. ovum)
• EGG, AUGUSTUS LEOPOLD (1816-1863)

egg albumin . All albumins are laevo-rotatory; and on incineration a small amount of inorganic ash is invariably See also:

• LEFT

left . They are usually insoluble in See also:

• WATER

water, See also:

• ALCOHOL

alcohol and See also:

• ETHER, (C2H5)2O

ether; and their presence as solutes in vegetable and animal fluids is not yet perfectly under-stood, but it is probably to be connected with the presence of salts or other substances . A remarkable See also:

• CHANGE (derived through the Fr. from the Late Lat. cambium, cambiare, to barter; the ultimate derivation is probably from the root which appears in the Gr. «a urmu', to bend)

change occurs when many albumins are boiled with water, or treated with certain acids, their solubility and general characters being entirely altered, and the fluid becoming coagulated . This change is seen II General See also:

• CHAR (Salvelinus)

char-asters . in the transformation of the " See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white " of an egg on boiling . Albumins are generally detected by taking See also:

• ADVANTAGE

advantage of this See also:

• PROPERTY

property, or of certain See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour changes . The reagents in See also:

• COMMON

common use are: Millon's reagent, a See also:

• SOLUTION (from Lat. solvere, to loosen, dissolve)

solution of mercuric nitrate containing nitrous See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid, this gives a See also:

• VIOLET

violet-red coloration; nitric acid,. which gives a yellow colour, turning to See also:

• GOLD
• GOLD [symbol Au, atomic weight 195.7(H = 1),197.2(0 =16)]

gold when treated with See also:

• AMMONIA (NH3)

ammonia (xanthoproteic reaction); fuming sulphuric acid, which gives violet solutions; and See also:

• CAUSTIC (Gr. rcavvraubs, burning)

caustic potash and See also:

• COPPER (symbol Cu, atomic weight 63.1, H=1, or 63.6, O = 16)

copper sulphate, which, on warming, gives a red to violet coloration (biuret reaction) . Boiling with dilute See also:

• MINERAL

mineral acids, or baryta water, decomposes albumins into carbon dioxide, ammonia and fatty amino- and other acids . These decomposition products include: Decom" 1 cocoll or aminoacetic acid, NH2CH2COOH, position g y ' products. or aminopropionicacid,See also:

• CH3

CH3•CH(See also:

• NH2

NH2)•000H,a-amino- butyric acid, a-aminovalerianic acid, leucin or isobutyla-aminoacetic acid, (CH3)2CH•See also:

• CH2
• CH2(OH)

CH2•CH(NH2)•000H, isoleucin, probably 0-aminocaproic acid, serin or a-amino-f3-hydroxypropionic acid, HO•CH2•CH(NH2)•COOH, aspartic acid or aminosuccinic acid, HOOC.CH2.CH(NH2)•COOH, glutaminic acid or a-amino-n-glutaric acid,H000• (CH2)2• CH(NH2) • See also:

• COON

COON, diaminoacetic acid, a-13-diaminopropionic acid, lysin. or a-e-diamino-n-caproic acid, NH2(CH2)4 . CH (NH2) • COON, arginin or See also:

• GUANIDINE, CN3H5

guanidine-a-amino-n-valerianic acid, (NH) (NH2) C•NH• (CH2)3•CH(NH2)•COOH, ornithin or ab-diamino valerianic acid, NH2.(CH2)3.CH(NH2)•000H, histidin or a-amino-/3-imidazol- I propionic acid, HOOC . CH(NH2) • CH2 .

C : CH .N :CH • NH, proline i I or a -pyrrolidin carboxylic acid, HOOC•CH•NH•CH2•CH2•CH2, hydroxyproline, phenyl alanine or phenyl-a-aminopropionic acid, C61-15 . CH2• CH (NH2) . COOH,tyrosine or p-hydroxyphenyl-aaminopropionic acid, . phenyl ethylamine, p-hydroxyphenyl ethylamine, tryptophane or indol aminopropionic acid, A. cystin (protein-cystin) or a-amino-$-thioglyceric acid " disulphide," (S . CH2• CH(NH2) • COOH) 2, B. cystin (See also:

• STONE
• STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
• STONE, CHARLES POMEROY (1824-1887)
• STONE, EDWARD JAMES (1831-1897)
• STONE, FRANK (1800-1859)
• STONE, GEORGE (1708—1764)
• STONE, LUCY [BLACKWELL] (1818-1893)
• STONE, MARCUS (184o— )
• STONE, NICHOLAS (1586-1647)

stone-cystin), or a-thio-fl-aminoglyceric acid " disulphide," (NH2•CH2•CH : S . COOH)2 . This See also:

• LIST (O.E. lisle, a Teutonic word, cf. Dut. lust, Ger. Leiste, adapted in Ital. lista and Fr. lisle)
• LIST, FRIEDRICH (1789-1846)

list is not exhaustive; other products are given in Gustav See also:

• MANN, HORACE (1796-1859)

Mann, Chemistry of the Proteids (1906), to which reference should be made for a See also:

• COMPLETE

complete See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

account of this. class of compounds . The complexity of composition militates in a See also:

• GREAT

great measure against a rational See also:

• CLASSIFICATION (Lat. classis, a class, probably from the root cal-, cla-, as in Gr. icaMce, clamor)

classification of albumins by purely chemical considerations . Such classifications have been at- .assm- tempted by A . Kossel and by W . Kiihne and E . P . Pick; See also:

• CANON

canon of albumins. but in the See also:

• PRESENT

present See also:

• STATE
• STATE, GREAT OFFICERS OF

state of our knowledge, however,- the older classification of E .

Dreschel and F . Hoppe-Seyler, based primarily on solubilities and See also:

• DISTRIBUTION (Lat. distribuere, to deal out)

distribution, may be conveniently retained . This classification is with certain modifications as follows: I . Albumins proper: characterized by having colloidal solutions . Albumins: serum-albumin, egg-albumin, lactalbumin . Globulins: serum-globulin, egg-globulin, lactoglobulin, See also:

• CELL (from Lat. cella, probably from an Indo-European kal —seen in Lat. celare, to hide; another suggestion connects the word with Lat. cera, wax, taking the original meaning to refer to the honeycomb)

cell-globulins . Plant-globulins and plant-vitellines . Fibrinogen . Myosin . See also:

• PHOSPHORUS (Gr. 4ws, light, sPEpety, to bear)

Phosphorus containing albumins (nucleo-albumins), caseins, vitellines, nucleo-albumins of the cell-See also:

• PROTOPLASM

protoplasm, mucoid nucleo-albumins . (7) Histones . (8) Protamines .

II . Transformation products of the albumins proper . (i) Acid-albumins, See also:

• ALKALI

alkali albuminates . (2) Albumoses, peptones and peptides . (3) Halogen-albumins, oxyprotein, oxyprotsulphonic acid, &c . (i) Nucleo-proteids . (2) Haemoglobin and allied substances . (3) Glyco-proteids, mucins, mucoids, helico-proteid.IV . Albuminoids . (r) Collagen . (2) Keratin . (3) Elastin .

(4) Fibroin . (5) Spongin, &c . (6) Amyloid . (7) Albumoid . (8) Colouring matters derived from albumin . Albumins proper.—Albumins (as classified above) are soluble in water, dilute acids and alkalies, and in saturated neutral See also:

• SALT (a common Teutonic word, cf. Dutch zout, Ger. Salz, Scand. salt; cognate with Gr. &Xs, Lat. sal)
• SALT, SIR TITUS, BART

salt solutions; they are coagulated by See also:

• HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

heat . " Serum-albumin," or " See also:

• BLOOD

blood-albumin," possibly C4i H7nNusSSOi4o, occurs in blood-serum, See also:

• LYMPH

lymph, chyle, See also:

• MILK (0. Eng. meoluc; from a common Indo-European root, cf. Lat. mulgere, Gr. ?t dXyetv)

milk, &c.; its coagulation temperature is about 67° . It differs from egg-albumin in its specific rotation (–57° to -64°), and in being slowly coagulated by alcohol and ether . Egg-albumin is the See also:

• CHIEF (from Fr. chef, head, Lat. caput)

chief constituent of the white of egg; this fluid also contains a globulin and a mucoid . It coagulates at about 56°, and its specific rotation is -30• 70° . " Lact-albumin " occurs in all kinds of milk . The globulins are insoluble in water and in dilute acids, but soluble in alkalies and in neutral salt solutions; these solutions are coagulated on boiling .

" Serum-globulin," also termed globulin or fibrino-plastic globulin, paraglobulin and paraglobin; occurs in blood serum; " cell-globulins " occur in many See also:

• ORGANS

organs See also:

• DIVER

diver, kidneys, See also:

• PANCREAS (Gr. rag, all; 1cpks, flesh)

pancreas and the See also:

• THYROID (Gr. Ovpoea3i'is, shield-shaped, from Ovpeos, a large oblong shield, shaped like a door, Obpa, and eiSos, form)

thyroid gland, also in muscle-plasma; " crystalline," a globulin occurring in two forms a and 13, is found in the See also:

• LENS
• LENS (from Lat. lens, lentil, on account of the similarity of the form of a lens to that of a lentil seed)

lens of the See also:

• EYE
• EYE (O. Eng. edge, Ger. Auge; derived from an Indo-European root also seen in Lat. oc-ulus, the organ of vision (q.v.)

eye; " egg-globulin " and " lactoglobulin " occur respectively in the white of egg and in milk . , Plant albumins or phyto-albumins have been chiefly investigated in the See also:

• CASE
• CASE, JOHN (d. 1600)

case of those occurring in seeds; most are globulins, insoluble in pure water, but soluble in salt solutions; " Q edes'See also:

• TIN (Lat.- stannum, whence the chemical symbol " Sn "; atomic weight =117.6, 0=16)

tin," a globulin of this class, is very widely distributed . Other varieties or classes of these compounds are: plant caseins; phyto-vitellines, legumins and conglutins . Fibrinogen occurs in the blood plasma, and is changed by a ferment into See also:

• FIBRIN, or FIBRINE

fibrin, to which the clotting of blood is due . Fibrinogen is insoluble in water, but soluble in salt solutions; it has three different coagulation temperatures, 56°, 67 75° . Fibrin, produced from fibrinogen by a:ferment, is a jelly-like substance; coagulable by heat, alcohol, &c . The muscle-albumins include " myosin " or paramyosinogen, a globulin, which by coagulation induces rigor mortis, and the closely related " myosinogen " or myogen; myoglobulin and myoalbumin are also found in muscles . The nucleo-albumins or phospho-globulins are insoluble in water and acids, but soluble in alkalies, and have an acid reac'tiOn . " Caseinogen " (after W . D . Halliburton) is the chief albumin of milk; its composition varies with the animal . It is insoluble in water, while its salts are readily soluble .

" Eucasein-'" is` the ammonium salt; " nutrose " and " plasmon " are See also:

• SODIUM [symbol Na, from Lat. natrium; atomic weight 23.00 (0=16)]

sodium salts . By the rennet ferment caseinogen is converted into casein, a substance resembling caseinogen in being soluble''in water, but differing in having an insoluble See also:

• CALCIUM [symbol Ca, atomic weight 40.0 (o= x6)]

calcium salt . The formation of casein involves the curdling of milk . Other phosphoglobulins are vitelline, found in the yolk of hens' eggs, and ichthulin, found in the eggs of See also:

• FISH (O. Eng. fist, a word common to Teutonic languages, cf. Dutch visch, Ger. Fisch, Goth. fisks, cognate with the Lat. piscis)
• FISH, HAMILTON (1808-1893)

fish . Histone.r lre class of albumins soluble in water and acids, but essentially basic in See also:

• CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character; hence they are precipitated by alkalies . It is remarkable that many histones are soluble in an 'excess df alkali . They do not exist in a See also:

• FREE

free state, but in See also:

• COMBINATION (Lat. combinare, to combine)

combination with a " prosthetic group " (after A . Kossel) they give rise to important cell constituents—haemoglobin, nucleo-proteids &c, " Thymus histone " occurs in the thymus gland; globin occurs in combination as haemoglobin; other histones have been extracted from the red blood corpuscles of the See also:

• GOOSE (a common Teut. word, O. Eng. gOs, pl. ges, Ger. Gans, O. Norse gas, from Aryan root, ghans, whence Sans. hansa, Lat. anser (for hanser)
• GOOSE (GAME OF)

goose and the testes of fishes and other animals . The protamines are a-well= characterized class of albumins found in the ripe spermatozoa' of fishes . Albumoses and Peptones.—The See also:

• PRIMARY

primary products of the See also:

• DISSOCIATION

dissociation of albumins are the abumoses,. characterized by not being coagulable by heat, more soluble than the albumins, having a far less complex composition, and `eApable of being"salted out " by certain salts, and the peptones, similar to albumoses but not capable of being " salted out "; moreover, peptones are less complex than albumoses . By further decomposition peptones yield peptides, a certain number of which have been synthesized by Emil Fischer and his collaborators . Albumoses and peptones are white powders, readily soluble in water, with the exception of the hetero-albumoses—a subdivision of primary albumoses .

They give the biuret and xanthoproteic reactions, and See also:

• FORM (Lat. forma)

form salts with both acids and bases . Albumoses and peptones are obtained by peptic digestion, the latter being termed peptic-peptones; tryptic digestion also produces peptones . Acids and moist heat induce similar changes . Proteids.—These substances are combinations of one or more albumins with a See also:

• RADICAL (Lat. radix, a root)

radical of an essentially different nature, termed by Kossel a " prosthetic group." It is convenient to classify proteids by those See also:

• GROUPS
• GROUPS, THEORY

groups . " Nucleo-proteids," constituents of the cell-See also:

• NUCLEUS (Lat. for the kernal of a nut, nux, the stone of fruit)

nucleus, are combinations of albumins and nucleic acid; they always contain See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron . They are loose, white, non-hygroscopic powders, soluble in water and salt solutions, and have an acid reaction; they give the colour reactions of albumins . Nucleic acid is at present of unknown constitution; decomposition products are: phosphoric acid, uracil or 2.6-dioxy-pyrimidin,l cytosin or 2-oxy-6-amino-pyrimidin, thymin . (nucleosin) or 2.6-dioxy-5-methyl pyrimidin hypoxanthin' or 6-oxypurin, xanthin or 2.6-dioxypurin, See also:

• ADENINE

adenine or 6 amino-See also:

• PURIN, C5H4N4

purin, guanine or 2-amino-6-oxypurin, pentoses (1-xylose), laevulinic acid, ammonia, etc . The nucleic acids vary with the source of the proteids, there being considerable See also:

• DIFFERENCES, CALCULUS OF (Theory of Finite Differences)

differences in chemical composition . In generA,i they are white, loose powders, slightly soluble in See also:

• COLD (in O. Eng. cald and ceald, a word coming ultimately from a root cognate with the Lat. gelu, gelidus, and common in the Teutonic languages, which usually have two distinct forms for the substantive and the adjective, cf. Ger. Kolte, kalt, Dutch koude

cold water, more soluble in hot water; they are precipitated by mineral acids, but dissolve in an excess . They are dextrorotatory, and the specific rotation is numerically greater than that of albumin; hence the proteids are, in general, dextrorotatory . An important nucleo-proteid is haemoglobulin or haemoglobin, the colouring matter of the red blood corpuscles of vertebrates; a related substance, haemocyanin, in which the iron of haemoglobin is replaced by copper, occurs in the blood of cephalopods and See also:

• CRAYFISH (Fr. ecrevisse)

crayfish .

Haemoglobin is composed of a basic albumin and an acid substance haematin; it combines readily with oxygen, carbon dioxide and carbon monoxide to form loose compounds (see NuTRITtoN) . It coagulates at 64° . By a dilute acid haemoglobin is decomposed into globin, and " haematin," a See also:

• FERRI, CIRO (1634-1689)
• FERRI, LUIGI (1826-1895)

ferri-See also:

• PYRROL, C4H5N

pyrrol derivative of the probable formula C34H34N4FeO5i under certain conditions the iron-free " haematoporphyrin " is obtained . This last substance may be reduced to mesoporphyrin, C34Hn8O4N4, which by further reduction gives haemopyrrol, CaH13N, possibly methyl-propyl-pyrrol or butyl-pyrrol . Other derivatives are haemin, haemochromogen and the haematinic acids . " Glyco-proteids " differ from nucleo-proteids in containing a See also:

• CARBOHYDRATE

carbohydrate radical, which is liberated only by boiling with mineral acids or alkalies . The mucins and mucoids belong to this group; they are acid and contain no phosphorus; they give the albumin colour reactions but are not coagulated by heat . Mucins occur in most of the slimy fluids of the See also:

• BODY

body; they vary in composition with their source . Mucoids resemble mucins in their composition and reactions, but differ, in general, in their physical properties . They occur in tendons, bones and See also:

• CARTILAGE (Lat. cartilage, gristle)

cartilage . The " phospho-glyco-proteids " resemble the mucins and mucoids in containing a carbohydrate See also:

• RESIDUE (through the French, from the Lat. residuum, a remainder, from residere, to remain)

residue, but differ in containing phosphorus . Ichthulin (see above) may be placed in this group; " helico-proteid," found in the serous gland of See also:

• HELIX (Gr. € tE, a spiral or twist)

Helix pomatia, the vineyard See also:

• SNAIL

snail, also belongs here .

Abbuminoids is the anatomical name given to albuminous substances forming the connective tissues . Chemically they resemble the albumins, being split up by acids or ferments into albumoses, peptones and amino-acids, forming salts, and giving N=CB ' The pyrimidin See also:

• RING (O.E. hring; a word common to Teutonic languages; and probably cognate with the Lat. circus, Gr. KtpKOS or KpLKOS, Skt'. chakra, wheel, circle, cf. also " harangue "); in art, a band of circular shape of varying sizes, made of any material and used f

ring is numbered 2C ,C5 . For the purin ring, see PuxrN . N—C 4 4the same colour reactions . They are quite insoluble in water and in salt solutions, and difficultly soluble in dilute acids and alkalies . Typical albuminoids are See also:

• GELATIN, or GELATINE

gelatin, keratin, elastin, fibroin, spongin and conchiolin . " Collagen " (Gr. ichXXa, See also:

• GLUE (from the O. Fr. glu, bird-lime, from the Late Lat. gluten, glus, glue)

glue, and See also:

• ROOT (late O.E. rot, adopted from Scand., cf. Norw. and Swed. rot, Dan. rod; the true O.E. word was wyrt, plant, represented in Ger. Wurz or Wurzel; the ultimate root is the same in both words, and is seen in Lat. radix)
• ROOT, ELIHU (1845– )

root yev- of yevvaeuv, to produce, ytyveuOat, to become), the ground-substance of bones and tissues, is decomposed by boiling water or on warming with acids into substances named gelatin, glutin or glue . Gelatin forms a white amorphous See also:

• POWDER (through O. Fr. puldre, modern poudre, from Lat. pulvis, pulveris, dust)

powder; the commercial product, however, generally forms glassy plates . The decomposition products are generally the same as with the general albumin; it gives the biuret reaction; forms salts with acids and alkalies, but is essentially acid in nature . Immersed in cold water gelatin does not dissolve but swells up; it dissolves readily in hot water, forming, according to the quantity present, a thick jelly which solidifies to a hard See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass on cooling (the " glue " of the See also:

• WOOD, ANTHONY A2 (1632-1695)
• WOOD, JOHN GEORGE (1827—1889)
• WOOD, MRS HENRY [ELLEN] (1814—1887)
• WOOD, SEARLES VALENTINE (1798—188o)

wood-worker), or a thin jelly (used in See also:

• COOKERY (Lat. coquus, a cook)

cookery) . Gelatin occurs also in the cornea and the sclerotic coat of the eye; and in fish scales, the latter containing 8o% of collagen, and 20% of ichthylepidin, a substance differing from gelatin in giving a well-marked Millon's reaction . Keratin (Gr .

Kipas, a See also:

• HORN
• HORN (a common Teutonic word, cognate with Lat. cornu; cf. Gr. Kipas)
• HORN (Lat. cornu; corresponding terms being Fr. cor, trompe; Ger. Horn; Ital. corno)
• HORN, ARVID BERNHARD, COUNT (1664-1742)
• HORN, PHILIP DE MONTMORENCY, COUNT

horn), the chief constituent of horny material, occurs in See also:

• HAIR (a word common to Teutonic languages)

hair, nails, hoofs and feathers . It is quite insoluble in water, dilute acids and alkalies . Related to this substance are "neuro-keratin," found in the medullary sheath of nerves, and " gorgonin," the See also:

• MATRIX

matrix of the axial See also:

• SKELETON

skeleton of the See also:

• CORAL

coral Gorgonio Cavolinii . Elastin occurs either as thick strands or as membranes; it. constitutes the " elastic See also:

• TISSUE (Fr. tissu, tissue, participle of tisser, Lat. texere, to weave)

tissue " of the anatomist . Its insolubility is much the same as keratin . "Fibroin " and See also:

• SILK

silk-glue or sericin occur in natural silk See also:

• FIBRES
• FIBRES (or FIBERS, in American spelling; from Lat. fibra, apparently connected either with filum, thread, or findere, to split)

fibres . Fibroin is insoluble in water, acids and alkalies; silk-glue resembles gelatin in its solubility, but it is less readily gelatinized . " Spongin," the matrix of See also:

• BATH
• BATH, THOMAS THYNNE
• BATH, WILLIAM

bath-sponge, is insoluble in water and dilute acids, but soluble in concentrated mineral acids . " Conchiolin," the matrix of shells of the See also:

• MOLLUSCA

mollusca, is only slightly soluble in acids . " Cornein " forms the framework of See also:

• CORALS (KoRAis), ADAMANTIOS [in French, DIAMANT CORAY] (1748–1833)

corals . " Amyloid " occurs as a pathological product, and also in the healthy aorta and in old cartilage . It is an albumin, and not a carbohydrate as was formerly held; and gives most of the colour reactions of albumins .

It forms shiny, homogeneous masses, quite insoluble in cold water and in salt solutions, but soluble in alkalies . The albumoids include, according to Cohnheim, substances which possess certain properties in common, but differ from the preceding groups . In general they resemble coagulated albumin, and also the gelatin-yielding tissues, but they themselves do not yield gelatin . Colouring matters derived from albumins include the " melanins " (Gr. ykX as, See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black), substances which differ very considerably in composition, the sulphur and iron content being by no means See also:

• CONSTANT, BENJAMIN (1845-1902)

constant; they do not give the reactions of albumins . The black colouring matter of hair, the skin of negroes, and of the See also:

• INK (from Late Lat. encaustum, Gr. gysavorov, the purple ink used by Greek and Roman emperors, from iyKaiew, to burn in)

ink bag of See also:

• SEPIA (Gr. a iria, cuttlefish)

Sepia have been examined . Melanins obtained from tumours form black, shiny masses; they are insoluble in water, neutral salt solutions, dilute acids and in the common organic solvents .