DISEASES CAUSED BY SPIROCH^TES 871 



has opened the question as to the identity of the two microorganisms. 

 According to most clinical observers, however, yaws, which is a 

 disease characterized chiefly by a generalized papular eruption, is 

 unquestionably distinct, clinically, from lues, and experiments of 

 Neisser, Baermann, and Halberstadter, 59 as well as of Castellani 60 

 himself, have tended to show that there is a distinct difference 

 between the immunity produced by attacks of the two diseases. 

 The disease is transmissible to monkeys, as is syphilis. 



SPIROCH^TA GALLINARUM 



An acute infectious disease occurring among chickens, chiefly in 

 South America, has been shown by Marchoux and Salimbeni 61 to be 

 caused by a spirochaete which has much morphological similarity to 

 the spirochaete of Obermeier. 



The disease comes on rather suddenly with fever, diarrhea, and 

 great exhaustion, and often ends fatally. The spirochaete is easily 

 demonstrated in the circulating blood of the animals by staining 

 blood-smears with Giemsa's stain or with dilute carbol-fuchsin. 



Artificial cultivation of the microorganism has not yet been 

 accomplished. Experimental transmission from animal to animal 

 is easily carried out by the subcutaneous injection of blood. Other 

 birds, such as geese, ducks, and pigeons, are susceptible; mammals 

 have, so far, not been successfully inoculated. According to the 

 investigation of Leviditi and Manouelian, 62 the spirochaates are 

 found not only in the blood but thickly distributed throughout the 

 various organs. 



Under natural conditions, infection of chickens seems to depend 

 upon a species of tick which acts as an intermediate host and causes 

 infection by its bite. The spirochaete, according to Marchoux and 

 Salimbeni, may be found in the intestinal canal of the ticks for 

 as long as five months after their infection from a diseased fowl. 



In the blood of animals which have survived an infection, ag- 

 glutinating substances appear and active immunization of animals 

 may be carried out by the injection of infected blood in which the 

 spirochaetes havo boon killed, either by moderate heat or by preserva- 



09 Neisser, Baermann, und Halberstadter, Miinch. mod. Wodi., xxviii, 1906. 



60 Castellani, Jour, of Hyg., 7, 1907. 



61 Marchoux et Salimbeni, Ann. de Tinst.. Pasteur, 1903. 

 K Levaditi et Manouelian, Ann. de Pinst. Pasteur, 1906. 



