60 SPIROCHjETES. 



Spirochaetes are also supposed to be responsible for 

 the diseases known as balanitis and ulcus tropicum 

 (see pp. 107, 103). 



DISEASES OF ANIMALS. 



A number of diseases in the lower animals are associ- 

 ated with the presence of Spirochaetes. The best known 

 is the so-called spirillosis of fowls, caused by the Sp. 

 gallinarum. The disease is characterised by weakness, 

 drowsiness and diarrhoea. It may prove fatal or 

 recovery may ensue. The anatomical lesions met with 

 consist in a fatty degeneration of the liver, with accu- 

 mulation of uninucleated cells round the vessels, and 

 hyaline necrosis in the spleen. The spirochastes are 

 found in and around the vessels, in their walls, and 

 between the cells of the liver. They do not usually 

 become intracellular, but may be found in the mature 

 ovules. Hereditary infection does not occur, the 

 offspring of infected fowls being immune. The 

 fertilised egg can, however, be artificially inoculated 

 and then the chick is born infected. In such chicks 

 the liver is first invaded and undergoes the change above 

 described. Haemorrhages also occur, and the blood is 

 described as "myeloid" or "embryonic" or both to- 

 gether (containing granular myelocytes, vacuolated 

 uninucleated cells, and nucleated red corpuscles with 

 basophile granules) . 



The Spirochaetes are agglutinated by the serum of the 

 infected birds. Levaditi considers that they are de- 

 stroyed by phagocytosis, carried out especially by the 

 macrophages of the liver and spleen. Neufeld and 

 Prowazek deny this, and attribute recovery to the 

 action of the serum, which is parasiticidal in vitro and 

 also capable of protecting other birds. Gabritchewsky 

 states that "lytic" bodies (bacteriolysins) appear in 



