2168 



ULCERATIONS 



The medium used by NicoUe for the cultivation of the parasite is a modifica- 

 tion of Novy-McNeal medium, and is composed as follows: — 



This is dissolved in a large flask in a Koch's stove, and then distributed in 

 tubes. After sterilization, to each tube is added one-third rabbit-blood, 

 collected with all aseptic precautions. The tubes are kept aslant for twelve 

 hours, then kept at 37° C. for five days, after which they are kept at the 

 ordinary temperature for some days before using. This medium is often 

 referred to as the N.N.N, medium. Row has introduced a simple hsemo- 

 globinized saline culture medium. 



Histopathology. — The histopathology of the disease has been 

 studied by Unna, Leloir, Kumm, Riehl, Wright, Strong, Bettmann 

 and von Vasielewski, Balfour, Archibald, Darling, and others. The 

 histological lesions in the common ulcerative variety consist essen- 

 tially in the atrophy and disappearance of the epidermis of the part, 

 and in a very extensive cellular infiltration of the corium and papillae 

 by various kinds of lymphoid cells, plasma cells, and numerous large 

 roundish cells containing a single faintly stained vesicular nucleus 

 and large amount of cytoplasm. These large roundish cells, which 

 are probably proliferated endothelial cells, contain often many 

 Wright's bodies closely packed together, occupying most of the 

 available space between the nucleus and the cell periphery. Darling 

 in his case found that the corium and papillae were inj&ltrated by 

 newly formed cells, .lymphoid, endothelial, epithelioid, giant, and 

 plasma cells. There were no necrotic areas, and a polymorphic 

 leucocytic infiltration was not noted. Many interpapillary down- 

 growths were seen in the rete. The squamous epithelium was sur- 

 rounded by a mass of desquamated epithelium forming the crust. 

 The lymphatic and bloodvessels in the deeper layers of the skin were 

 surrounded by collections of lymphoid cells. Balfour, Thomson, and 

 Archibald, noted the following principal histological features in their 

 cases: — presence of vertical epithelial columns extending deeply 

 downward, with a few cell-nests and isolated masses of cell infiltra- 

 tion. The dermis is infiltrated with cells of the large round type, 

 polymorphonuclear leucocytes, and large numbers of eosinophiles. 

 This cellular infiltration may extend to the sebaceous glands and 

 hair follicles. 



Communicability. — The disease may be conveyed by direct 

 infection from person to person, by absorption of the virus through 

 some pre-existing abraided surfaces, or small wounds or ulcers of 

 other nature present on the skin. The reservoir of the virus would 

 be in the affected persons and in dogs, which, as noted as long ago 

 as 1854 by Vuillemin, may suffer from a very similar or identical 

 affection. Certain authors have suspected geckoes and lizards to be 

 the reservoir, but this can hardly be, as these animals cannot be 

 experimentally infected. Camels, too, have been suspected to be a 

 reservoir of the virus. Insects, especially flies, probably play a 

 certain role in the transmission of the disease. That flies convey 



Agar 



Salt 



Water 



14 grammes. 

 6 



900 c.c. 



