4i8 



BIOLOGY OF THE LABORATORY MOUSE 



invasion of the liver following primary infection of the gastro-intestinal 

 tract. 



This disease is particularly interesting because of its limited host sus- 

 ceptibility. Further study from the point of view of heredity (go) has 



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Fig. 162. — Banded bacilli at the pcrii)hL'ry of a liver lesion in a mouse <lying of B. 

 piliformis inlection. Stained section (X1400). {From Tyzzer.) 





Fig. 163. — Smear of intestinal epithelium from a mouse dying of B. pUiformis 

 infection. Note intracellular bacilli having the appearance of spore-formation. 

 Spore stain. (X1400.) {From Tyzzer.) 



indicated that predisposition to infection is independent of the waltzing 

 factor, the dominant white factor, and sex. The condition, moreover, 

 may become of greater practical importance, since Tyzzer (297) has recently 

 found it in highly inbred stocks used for cancer studies. 



Van Rooyen (301) has inferred that this disease may be the same as 

 that produced by Streptobacilliis moniliformis. Apart from clinical difTer- 



