264 INFECTIOUS ENTERO-HEPATITIS 



protoplasm of a rather coarsely granular character inclosing spheres 

 which appear homogeneous. The giant cells are up to 30// in diameter. 

 Sections of liver tissue hardened in alcohol and in Foa's solution 

 were also examined. The foci of disease contain necrotic areas in which 

 are numerous giant cells each inclosing a number of microparasites. In 

 some portions there is much cell infiltration in the interlobular tissue 

 around the portal vessels. Among the cells the protozoa are recognizable. 



§ 194. DifTerential diagnosis. This disease is to be 

 differentiated from certain local affections of the caecum not 

 especially uncommon in turkeys. Ziirn (Deutsche Zeit. f. 

 Thiermed, X (1883). p. 189) has described a csecal disease in 

 water fowls and turkeys and Von Ratz has described a caecal 

 disease in turkeys in which the liver lesions seem to be absent. 

 The lesions in the liver and the presence of the microparasite, 

 as previously described, are sufficient to differentiate this 

 disease. 



§ 195. Prevention. The present knowledge of this 

 disease shows that the parasite is transmitted directly from 

 diseased to healthy turkeys. This suggests that the first pre- 

 caution is to avoid the entrance of diseased or seemingly 

 healthy turkeys from a diseased flock into a healthy one. 

 The discovery of Chester indicates that a like precaution must 

 be taken with reference to fowls. If the disease exists the best 

 though most radical method as suggested by Smith is the total 

 destruction of the affected flock, thorough disinfection and the 

 iritroduction of healthy turkeys. 



REFERENCES. 



1. Chester. Report of the bacteriologist of the Del. College Agric. 

 Exp. Station. 1899-1900. (C. reports disease in chickens). 



2. CuSHMAN. Nature of black head in turkeys. Report R. Island 

 Agric. Exp. Station. 1894. p. 199. 



3. Moore. The direct transmission of infectious entero-hepatitis 

 in turkeys. Circular No. 5, U. S. Bureau of Aniinal Industry. 1896. 



4. Smith. Infectious entero-hepatitis in turkeys. Bulletin No. S,, 

 U. S. Bureau of Animal Industry. 1895. 



