312 BULLETIN No. 161 [Novembc 



r, 



sidered that these germs are living, and this should then be verified 

 by culturing on media suitable for the growth of tubercle bacilli. 



L,KSIONS PRODUCED BY DEAD TUBERCLE BACILLI 



PURPOSE OF The purpose of these experiments was to deter- 

 MENTS mine the difference in effect of dead tubercle bacilli 



and of living germs when injected into guinea 

 pigs ; also to find a means of determining when lesions were pro- 

 duced by living and when by dead germs. In order to determine 

 this three experiments were made. 



For the first experiment a pure culture of the 

 EXPERIMENT I bovine type of tubercle bacilli was used. A heavy 



emulsion of fresh culture was made in sterile 

 distilled water. The emulsion, showed a distinctly milky appear- 

 ance. One cubic centimeter of this fresh emulsion was injected 

 subcutaneously into Guinea Pig 993. The remaining portion of 

 this emulsion was autoclaved at fifteen pounds pressure for ten 

 minutes. Two guinea pigs, Nos. 994 and 995, were each injected 

 subcutaneously with i cc. of the autoclaved emulsion. Guinea Pig 

 993 was killed 49 days later and showed generalized tuberculosis. 

 Guinea Pigs 994 and 995, killed respectively 85 and 50 days after 

 inoculation, were found to be healthy. Their weights continued 

 to increase from the time they were inoculated until killed, and 

 at no time did they show any physical signs of tuberculosis. 



Before the conclusion of the first experiment a 

 EXPERIMENT II second was started in which an eight-day culture 



of the same strain of bovine tubercle bacilli was 

 used. One milligram was removed and rubbed up in 4 cc. of 

 broth. One loopful of. this emulsion was diluted with 2 cc. of 

 broth and injected interperitoneally into Guinea Pig 1026. The 

 4 cc. of broth were pla,ced in streaming steam for one hour. 

 Guinea Pigs 1027 and 1028 were each injected interperitoneally 

 with 2 cc. of this steamed emulsion. Guinea Pig 1026 showed 

 physical signs of tuberculosis ten days after injection. No physical 

 signs of tuberculosis were observed in either of the two guinea 

 pigs (1027 and 1028) that were inoculated with the killed culture. 

 Thirty-five days after inoculation Guinea Pigs 1026 and 1027 were 

 injected with 2 cc. of the tuberculin. Guinea Pig 1026 died from 

 the effect of the tuberculin after eight hours; 1027 died after 

 eighteen hours. Autopsy of 1026 showed severe generalized tuber- 

 culosis; that of 1027 showed a few lesions in the liver and a very 

 slight enlargement of the inguinal lymphatics. Microscopic prep- 

 arations stained for tubercle bacilli revealed none of these organ- 



