198 EDWARD JENNER 



By a reference to the treatise on the Variolae Vaccinge 

 it will be seen that, in the month of April, 1798, four chil- 

 dren were inoculated with the matter of cow-pox, and 

 that in two of these cases the virus on the arm was de- 

 stroyed soon after it had produced a perceptible sickening. 

 Mary James, aged seven years, one of the children alluded 

 to, was inoculated in the month of December following with 

 fresh variolous matter, and at the same time was exposed 

 to the effluvia of a patient affected with the smallpox. The 

 appearance and progress of the infected arm was, in every 

 respect, similar to that which we generally observe when 

 variolous matter has been inserted into the skin of a person 

 who has not previously undergone either the cow-pox or the 

 smallpox. On the eighth day, conceiving there was infec- 

 tion in it, she was removed from her residence among 

 those who had not had the smallpox. I was now anxiously 

 waiting the result, conceiving, from the state of the girl's 

 arm, she would fall sick about this time. On visiting her 

 on the evening of the following day (the ninth) all I could 

 learn from the woman who attended her was that she felt 

 somewhat hotter than usual during the night, but was not 

 restless; and that in the morning there was the faint ap- 

 pearance of a rash about her wrists. This went off in a 

 few hours, and was not at all perceptible to me on my 

 visit in the evening. Not a single eruption appeared, the 

 skin having been repeatedly and carefully examined. The 

 inoculated arm continued to make the usual progress to the 

 end, through all the stages of inflammation, maturation, and 

 scabbing. 



On the eighth day matter was taken from the arm of this 

 girl (Mary James) and inserted into the arms of her mother 

 and brother (neither of whom had had either the smallpox 

 or the cow-pox), the former about fifty years of age, the 

 latter six. 



On the eighth day after the insertion the boy felt indis- 

 posed, and continued unwell two days, when a measles-like 

 rash appeared on his hands and wrists, and was thinly 

 scattered over his arms. The day following his body was 

 marbled over with an appearance somewhat similar, but he 

 did not complain, nor did he appear indisposed. A few 





