KXPOSURK OF A SIIKKP TO VAllIOI.A. 39 



on the capillaries, for us to be satisfied that variola 

 will follow its introduction. 



Several causes for the non-success of the case may 

 be assigned besides that alluded to ; and among them 

 may be mentioned the small quantity of the lymph we 

 employed ; also its age (for it was kept several days) 

 might have deteriorated it ; and even its original imr'ity 

 may be reasonably doubted, as it was the produce of 

 very large eruptive vesicles. We would likewise direct 

 attention to the state of the system of the sheep at the 

 particular period it was experimented on, as a reason 

 why it was not susceptible of the action of the virus, 

 for we subsequently succeeded in ovinating the same 

 animal. 



Whatever cause, or combination of causes, produced 

 the failure of the experiment, the result, nevertheless, 

 is not without its value. 



We shall now proceed to a description of the case 

 of THE Lamb mentioned at page 32, as being exposed 

 to the contagion of variola by confinement in a shed 

 with a sheep which was rapidly sinking from the 

 malady. The two animals were kept together for 

 eighteen hours, and no apparent ill-effect resulted until 

 October 14th, eleven days after the exposure, when the 

 lamb was found to refuse its food, and to give other 

 indications of disease : the pulse was quickened ; the 

 breathing laboured and painful ; the mouth hot ; the 

 ears pendent; the conjunctival membranes injected; 

 an augmented lachrymal secretion also existed ; the 

 skin was generally reddened, and on the lower lip three 

 papulae were observed, and one at the angle of the 

 mouth on the right side : no others were to be found 

 on any part of the body. 



