



893.] Experiments on Variola and Vaccinia. 187 



The possibility that the increase in the quantity of the lactic acid 

 may likewise assist, if not be a material cause, in producing the 

 nerve-symptoms, is also worthy of note. 



That sugar, acting as sugar, was not their cause was shown by the 

 symptoms not appearing until from a quarter to one hour after its in- 

 jection. That is to say, not till the quantity of sugar present in the 



ood had already markedly decreased. 



" 



XVIII. " Experiments on Variola and Vaccinia." By S.MONCK- 

 TON COPEMAN, M.A., M.D. (Cantab.). Communicated by 

 Professor M. FOSTER, Sec. R.S. Received June 14, 1893. 



In the course of some experiments on the bacteriology of vaccine 

 lymph, I was confronted by a difficulty in the practical testing of 

 certain of the results of my work. Continuous experimentation on 

 children being obviously out of the question, I was naturally led to 

 turn my attention to the discovery if possible, of some one or more 

 of the lower animals which, by reason of their passing through the 

 various stages of vaccination and more especially variolation in a 

 manner comparable with that witnessed in the human subject, might 

 serve me for control experiments. 



Little or no success having been obtained with the various 

 domestic animals, I next turned to the monkey tribe on account of 

 their similarity in many respects to man, although assured at the 

 time that they were not susceptible to either vaccinia or variola. 

 On putting the matter to the test, however, I found that this was 

 not the case, the inoculation of vaccine and of variolous lymph 

 having each of them given, in my hands, successful results in every 

 instance in which I have tried it on the monkey (JRhcesus). 



In the case alike of variola and of vaccinia, the local result of 

 inoculation attains its acme (qua vesiculation) in the monkey, as in 

 the human being, about the eighth day. The first signs of reaction 

 appear usually on the third day, by which time, if variolous lymph 

 has been used, there is a distinct, though very thin, crust over the 

 site of inoculation. By the fifth day vesiculation has generally com- 

 menced, this becoming more obvious up to the eighth day, though 

 even, then it is much less marked in variolous cases than in those 

 which have been vaccinated, the difference being easily recognisable. 



Later the vesicle gives rise to a pustule, by which time there is not 

 infrequently considerable swelling of the skin and subcutaneous 

 tissue and of the nearest lymphatic glands. The pustule gradually 

 dries up, and a scab is formed which, is more pronounced after 

 vaccination than variolation, and which falls off some time during 

 the third week, if the monkey has not picked it off before. 



