3«i 
immense numbers, and tangles are common ; they 
disappear again before death. 
Morphology. —10-20/^ 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. —(1) 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. —10-20 ^ 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. 
