THE ALIMENTARY CANAL AS A SOURCE OF CONTAGION 23 



They require little comment ; they speak for themselves. The carcase 

 in each case was free from evidence of disease which could be detected 

 with unaided vision, yet, in both, the contents of the intestine were 

 swarming with a specific bacillus which proved to be anaerobic, and 

 which when inoculated into a fresh sheep rapidly killed it with evidence 

 of intense local reaction. The disease germ, moreover, could be passed 

 from host to host, evidently gaining in virulence by its transit. 



The intestine the portal of entrance in the case of all the members of the 

 group. — Not only in the case of Louping-ill, but in that of all the other 

 members of the group the intestine seems to be the portal through 

 which the organism gains entrance, and the fact that the peritoneal 

 cavity contains it, more than any other cavity or any organ in the 

 body, is thus readily enough explained. The peritoneal cavity is 

 evidently the great lymph-sac of the body. Not only do its walls 

 contain the lymph-vessels in connection with the intestine, but evidently 

 those lymph-vessels returning from the hind limbs have also a free, 

 although perhaps circuitous, connection with its interior. The organism 

 of Louping-ill fails to propagate on the blood, but grows freely enough 

 on the secretion of the peritoneal membrane, hence the large quantity 

 of bacillus usually found in the liquid. 



When the organism of the disease is inoculated subcutaneously in 

 the sheep, death takes place so suddenly, evidently from acute toxic 

 poisoning, that time and opportunity are not afforded for the develop- 

 ment of the nervous phenomena. Where the organism, on the contrary, 

 is introduced into the alimentary canal, and where the animal takes the 

 disease but lives over, it may be, several weeks, the nervous symptoms 

 are well developed. 



Production of immunity to the disease, — It would be apart from the 

 object of this communication to enter into the explanation of the 

 production of immunity to the disease too minutely, and the reader is 

 again referred to the Board of Agriculture Report (loc. cit.), already 

 mentioned, for a full statement of the case. 



The bacillus of Louping-ill can be administered to sheep by the 

 mouth with impunity throughout the greater part of the year. As the 

 susceptible months are approached, however, namely, March, April, and 

 May, the danger of doing so is extreme, and a fair proportion of the 

 animals so treated will die with all the classical symptoms. At other 



(23) 



