72 



Proceedings of the Royal Irish Academy. 



The glands near to the bowel-wall appeared to have borne the 

 brunt of the infection. Those further away in the mesentery were 

 apparently free frem lesions, l^o tuberculous lesion could be found 

 elsewhere. 



Inoculation of the caseous material taken from a mesenteric 

 lymphatic gland into a rabbit remained without effect. The rabbit 

 did not develop even a local lesion. The inference, therefore, is that 

 the lesion was innocuous : that the animal had recovered from the 

 infection. 



The case is of great interest, because— /rs^, a single dose of 

 virus was able to infect ; second^ infection was readily revealed at the 

 fiftieth day by tuberculin ; third^ after the lesion had become sterile, 

 tuberculin gave no reaction, and this again emphasized the value of 

 tuberculin as a diagnostic reagent ; fourth^ it supports the contention 

 that animals recover from infection by virus of low potency. It will 

 be interesting to learn if, as is maintained by Calmette and Guerin^ 

 immunity from tuberculosis may be brought about by the use of 

 doses of virus of lov/ virulency given by tlie alimentary tract. 



II. — Note on the Pkesence of Tubercles in the Lacteals or the 

 Villi of the Intestine in Tubeeculotts Infection. 



Infection in tuberculosis, probably in the great majority of cases, is 

 infection by the alimentary tract. This opinion is being forced upon 

 investigators who have paid particular attention to experimental 

 tuberculosis induced by feeding with contaminated or infective 

 materials. In some cases the virus may pass through the mucous 

 membrane of the intestine without producing a visible lesion ; at 

 other times necrosis and ulceration of the intestine are established. 

 Probably the explanation of the different results obtained is to be 

 found in the amount and degree of virulence of the infective agent 

 employed. In cases where there are macroscopic lesions there is no 

 difficulty in tracing the course of the virus in the intestinal wall, 

 particularly to the mesenteric lymphatic glands situated in the 

 mesentery. In other cases the blood capillaries may take up the 

 virus, and lesions develop in consequence in the liver, the organ 

 where the virus is first arrested. The point to be ascertained in both 

 forms of infection is how do the bacilli pass through the intestinal 

 mucous membrane. The tubercle bacilli are non-motile and are 

 incapable per se of passing through the epithelial covering of the 



