CHAPTER VIII 



THE SPLIT PRODUCTS OF THE TUBERCLE 



BACILLUS AND THEIR EFFECTS 



UPON ANIMALS 1 



The Organism. The tubercle bacillus employed in the 

 experimental work herewith reported is one which, after 

 having been grown for many years on artificial culture- 

 media, has lost its virulence for rabbits and guinea-pigs. 

 We have repeatedly demonstrated this fact during the 

 past six years, but in order to have renewed evidence we 

 have, at the beginning of this research, inoculated 4 rabbits 

 and 5 guinea-pigs intra-abdominally with loops of the 

 glycerin beef-tea culture, and these animals having been 

 killed from three to six months after inoculation, have in 

 no instance showed any evidence of infection. On artificial 

 culture-media this bacillus grows abundantly, and in this 

 respect it has served our purpose in furnishing a large 

 amount of cellular substance. It has been grown in the 

 ordinary glycerin beef-tea and has been harvested after 

 periods of from one to six months. Growths obtained 

 after from one to two months at 37 have given us the 

 most satisfactory material. 



The Cellular Substance. The bacterial substance is 

 collected on hard filters, dried between folded filters, and 

 thoroughly extracted, first with alcohol and then with 

 ether, in large Soxhlets. In this paper we will say nothing 

 concerning the fats and waxes extracted with alcohol and 

 ether. The cellular substance is next rubbed up in a mortar 

 and passed through a fine-meshed sieve. As thus prepared, 



1 The first part of this chapter is taken from a paper read by Vaughan 

 and Wheeler before the International Congress on Tuberculosis in 1908. 



