ACTINOMYCOSIS (STREPTOTRICHOSIS)  , a chronic infective disease occurring in both cattle and man . In both these groups it presents the same clinical course, being characterized by chronic inflammation with the formation of granulomatous tumours, which tend to undergo suppuration, fibrosis or calcification . It used to be believed that this disease was caused by a single vegetable parasite, the Ray-Fungus, but there is now an overwhelming mass of observations to show that the clinical features may be produced by a number of different species of parasites, for which the generic name Streptothrix has been generally adopted . In 1899 the committee of the Pathological Society of London recommended that the term Streptotrichosis should be used as the appropriate clinical epithet of the large class of Streptothrix infections . And since that year the name Actinomycosis has been falling into disuse, and in any case is only used synonymously with Streptotrichosis . For a further account of these parasites see the articles on BACTERIOLOGY and on PARASITIC DISEASES . Pathological Anatomy.—The naked-eye appearance of the different organs affected by Streptothrix infection varies according to the duration and acuteness of the- disease . In some tissues the appearance is that of simple inflammation, whereas in others it may be characteristic . The liver when affected shows scattered foci of suppuration, which may become aggregated into spheroidal masses, surrounded by a zone of inflammation . In the lungs the changes may be any that are produced by the following conditions . (I) An acute bronchitis . (2) A phthisical lung, grey nodules being scattered here and there almost exactly simulating tuberculous nodules .

(3) An acute broncho-

pneumonia with some interstitial fibrosis and a tendency to abscess formation . The most characteristic lesions are in the skin . These appear as nodules, sarcomatous-looking, soft and pulpy . Their colour is mottled, yellow and purplish red . The skin over them is thinned out, and broken down in places to form one or two crateriform ulcers from which a clear sticky fluid exudes . The size varies from that of a pea to a small orange . The pus is characteristic, varying in consistency though usually viscid, and containing numerous minute specks . The disease is more common in males than in females, and more prevalent in Germany and Russia than in England . The infection is probably spread by grain (corn or barley), on which the fungus may often be found . In a great number of recorded cases the patient has been following agricultural pursuits . The disease can only be transmitted from one individual to another with considerable difficulty, and no case of direct transmission from animal to man has yet been noted . Clinical History.-The course of actinomycosis is usually a chronic one, but occasionally the fungus gets into the blood, when the course is that of an acute infective disease or even pyaemia .

The symptoms are entirely dependent on the

organ attacked, and are in no way specially characteristic . During life a diagnosis of phthisis is continually made, and only a microscopic examination after death renders the true nature of the disease apparent . The nature of the skin "lesion is the most evident, and here the parasite can be detected early in the illness . The,- only drug which appears to have any beneficial influence on the course of the disease is potassium iodide, and this has occasionally been used with great benefit . Surgical interference is usually needed, either excision of the part affected, or, where possible, a thorough scraping of the lesion and free application of antiseptics .