548 Professor David James Hamilton [March 8, 



Surface cultures on glucose agar grow luxuriantly ; along the 

 central streak formed by "the inoculating wire, and from each side of 

 this, somewhat arborescent processes extend outwards, rendering the 

 sides of the central streak very irregular. Such cultures are not 

 particularly diagnostic. 



The stab-culture on glucose-gelatin, grown at 21° C, however, 

 is very characteristic. In" order to observe it, the gelatin should be 

 covered with olive oil, and the inoculation made with the platinum 

 wire through this. Quite a week will elapse before the growth reaches 

 its best. 



From the surface there passes downwards a grey- coloured streak 

 for a distance of a centimetre or so, but underneath this the culture 

 becomes more expanded and often flattened out in a single lamella 

 w^hose borders are occupied with a series of loop-like festoons. 

 Brush-like arms are subsequently thrown out from the central streak. 

 It liquefies the gelatin in course of time, but slowly, and when lique- 

 faction around the culture is complete, the organism falls down in a 

 greyish-coloured deposit. Gas-bells may or may not be liberated ; 

 sometimes there is a single gas-bell at the deepest part. 



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 those lymph-vessels returning from the hind limbs have evidently 

 a free, although perhaps circuitous, connection with its interior. The 

 organism of Louping-ill fails to propagate on the blood during life, 

 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 

 development 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 lecture to enter into the explanation of the pro- 

 duction of immunity to the disease too minutely, and those of my 

 audience interested in the matter are referred to the Board of 

 Agriculture Report {loc. cit.) for a full statement of the facts. 



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, 



