340 SCIENCE PROGRESS. 



tubercle bacilli, and the localisation of the disease must 

 be ascribed to the smallness of the dose given, inasmuch as 

 in some of the other animals inoculated with material from 

 the same source a spread of the disease was exhibited. It 

 is evident from this that the localisation of the tuberculous 

 lesion to the seat of infection may be due to the smallness 

 of the dose, and not solely to the resistance of the body to 

 the invasion of the bacillus ; or, to put it in other words, the 

 smallness of the dose enables the tissues to successfully 

 localise the disease. 



Although the results of these inoculation experiments 

 are suggestive, they yield in interest to those which result 

 from feeding with tuberculous material. When guinea-pigs 

 are fed with virulent tuberculous material a local lesion in 

 the intestines or csecum is always developed, and a sub- 

 sequent invasion of the lymphatic glands in connection with 

 the caecum and intestine occurs. The disease then spreads 

 to the cceliac glands and to the liver and spleen, and sub- 

 sequently to the posterior mediastinal and bronchial glands 

 and to the lungs ; finally, all the glands in the body may be 

 affected. The earliest time at which a local lesion was 

 discoverable in the intestine was eighteen days, and in 

 about six to eight weeks most of the organs of the body 

 are affected. Here, again, in the guinea-pig there is 

 evidence of the spread of tuberculosis along the lymphatic 

 channels. The cases in guinea-pigs in which, after feeding, 

 tuberculosis tended to become localised were those in which 

 either a small dose of virulent milk was given or a dose of 

 very slightly virulent milk. Thus, four guinea-pigs were 

 fed during the course of two days with 200 c.c. of milk which 

 was only slightly virulent ; one died in twenty-five days, 

 and showed no tuberculosis ; the second, third and fourth 

 died respectively in forty-nine, fifty-three, and sixty-seven 

 days. These three developed tuberculosis ; but the disease 

 was present in the intestines and mesenteric glands only in 

 the first two, and in the mesenteric glands only in the 

 third. In forty-nine days, when virulent milk was given, the 

 disease had usually extended to the liver and spleen and the 

 lymphatic glands of the body. The case of the third animal, 



