immense numbers, and tangles are common ; they 

 disappear again before death. 



Morphology. 10-20/4 long. The spirochaetes are 

 said to be surrounded with flagella. 



Pathogenicity. Young chickens and ducks to a 

 less extent are susceptible. 



Pathology. The spleen is soft, and there are 

 caseous foci in the liver. 



9. Sp. gallinarum. The cause of a fatal disease of 

 poultry in Brazil, and probably in many other countries. 



Symptoms. (i) Fever, (2) acute diarrhoea, (3) 

 anaemia, (4) somnolence, (5) convulsions. Death in 

 four to five days, or the hens may die in a condition of 

 cachexia in about a fortnight. 



Blood Examination. During the pyrexia, parasites 

 get more and more abundant, forming thick tangles. 

 They disappear again, frequently quite suddenly, 

 before death. 



Morphology. IO-2O/* long, with many undulations 

 (Fig. 117). According to some authors the spirochaete 

 is surrounded with flagella ; while Prowazek, on the 

 contrary, describes an undulating membrane in macer- 

 ated specimens. 



Pathogenicity. Geese, ducks, doves, sparrows and 

 rabbits (slight infection) are susceptible. 



