xiv] 



BACILLUS TUBERCULOSIS 



343 



cent, of milch cows are tubercuLir, and though in many 

 cases their milk is not different from the milk of normal 

 cows, and no tubercle bacilli can be detected, the same 

 milk injected into the peritoneal cavity of guinea-pigs never- 

 theless produced miliary tuberculosis in the peritoneum, 

 spleen, and liver. Out of twenty series of experiments only 

 once could the tubercle bacilli be demonstrated in the milk, 



Fig. 134. — A single Giant-cell, fIvum a similar Steciivien as in I'Receding 



I-IGUKE. 



The ring-like arrangement of the tubercle tjaciUi and tlie nuclei around tlicnr arc well 

 shown. (A. Pringle.) 



and yet in ten such experiments in which the milk did not 

 show tubercle bacilli, it nevertheless produced tuberculosis 

 on intra-peritoneal injection. Hirschberger explains these 

 results by assuming that though tubercle bacilli were not 

 jjresent in the milk as bacilli, their spores must have been 

 present. 



