TUBERCULOSIS. 229 



he succeeded in the fc«-tieth. Other observers, however, 

 have been more successful, and in two rabbits I was able 

 to produce tuberculosis by injection into the peritoneal 

 cavity of the raw juice expressed from the intercostal 

 muscles of a tuberculous cow after all tuberculous pleura 

 had been carefully " stripped " ; whilst the juice taken 

 from the muscle of the thigh injected into two other rabbits 

 was perfectly innocuous. The danger of infection by the 

 consumption of meat from tuberculous cows may have been 

 much exaggerated, but that there is a very appreciable 

 danger must most certainly not be lost sight of by our 

 Medical Officers of Health and the Veterinary Inspectors of 

 the Board of Agriculture. 



Koch, as we have seen, had discovered a specific or- 

 ganism which he had been able to cultivate outside the 

 body ; he had inoculated and produced tubercle ; and he 

 had found certain germicidal agents which were capable of 

 destroying the organism outside the body. He, and the 

 many interested workers who had investigated the subject, 

 had found that it was more difficult to inoculate certain 

 animals successfully than others. It had been observed even 

 that certain individuals of the same species were much more 

 refractory to the action of the virus than others, and it 

 very naturally suggested itself to those workers, that there 

 were two conditions which would have to be determined 

 before any systematic and organized attack could be made 

 on the tubercle bacillus within the body. The tubercle 

 bacillus itself might be developed under such conditions that 

 its virulence might be more or less modified. For example, 

 Koch found that all his cultivations made on blood serum 

 retained their power of growing in animal tissues in a most 

 extraordinary degree, and for long this substance was the 

 only nutrient medium used for the cultivation of the tubercle 

 bacillus. It was found, indeed, that the other combinations 

 used for the cultivation of other organisms up to that time 

 were valueless as nutrient substrata for the tubercle bacillus. 

 Nocard and Roux, however, found, as we have seen, that on 

 the addition of a certain percentage — 6-8 per cent. — of 

 glycerine to peptonized broth, solidified by the addition of 

 agar, they could obtain a nutrient medium on which the 

 tubercle bacillus would grow most luxuriantly. After it had 

 passed through several generations of cultivations on this 



