THE ALIMENTARY CANAL AS A SOURCE OF CONTAGION 1 7 



the organism gains entrance to the body of the sheep and to the 

 peritoneal cavity, next engaged my attention. A common notion is 

 prevalent among sheep-farmers that the tick has something to do with 

 its transmission, but the theory is not supported by any well- 

 grounded evidence founded on reliable observation. The tick, after 

 hibernating upon rough dry scrub and rank grass, becomes parasitical 

 upon the sheep during the month of April, and hence probably the 

 origin of the supposed aetiological relationship. Suffice it to say, 

 however, that, having sifted the matter very thoroughly, our Committee 

 did not acquire evidence corroboratory of the allegation. Even 

 although the organism may be present in the body of the tick, or, 

 what is much more likely, merely adherent to its surface, the data 

 at our command failed to prove that it is ejected from the rostrum 

 into the skin of the sheep, and that the disease spreads from 

 the tick-puncture as a centre. Many of the carcases had not a single 

 tick upon them, nor might there be evidence of a tick-bite. We never 

 made out that local oedema, gas-formation, or haemorrhage developed in 

 the vicinity of the tick-bite, and in the case of an organism exciting 

 such extreme local reaction as the bacillus of Louping-ill does, this 

 seems strong a priori evidence against the theory of the transmission of 

 the disease through the agency of the tick or any other animal parasite. 



Nevertheless, if sheep taken from uninfected land be put upon that 

 which is infected during the Louping-ill season, probably from a half to 

 two-thirds, or it may be the whole of them, will be dead in from three 

 weeks to a month afterwards. 



The first case that really opened my eyes to the point of entrance of 

 the organism was that of a lamb admitted to the Observation Station at 

 Kielder during our second season, and in the year 1903. 



A Cheviot lamb, perhaps about one month old, arrived at the Station 

 at Kielder on May 14th, 1903. 



The animal could walk, but in an uncertain swaying manner. The 

 posterior limbs and hind part of the trunk gave way occasionally, and 

 the animal fell on its side. The fore limbs and head maintained their 

 natural posture, and even the hind quarters could in a manner be raised 

 by an effort on the part of the animal, but soon again gave way. When 

 leaning against a fence it would remain erect for a considerable time, 

 seemed to be perfectly conscious so far as could be judged, did not 



(17) C 



