182 EDWARD JENNER 



Fourthly : From matter produced on the human skin from 

 contact with some peculiar morbid matter generated by a 

 horse. 



On these subjects I shall offer some comments: First, 

 to what length pustulous diseases of the udder and nipples 

 of the cow may extend it is not in my power to determine; 

 but certain it is that these parts of the animal are subject to 

 some variety of maladies of this nature; and as many of 

 these eruptions (probably all of them) are capable of giving 

 a disease to the human body, would it not be discreet for 

 those engaged in this investigation to suspend controversy 

 and cavil until they can ascertain with precision what is and 

 what is not the cow-pox ? 



For example: A farmer who is not conversant with any 

 of these maladies, but who may have heard of the cow-pox 

 in general terms, may acquaint a neighbouring surgeon that 

 the distemper appears at his farm. The surgeon, eager to 

 make an experiment, takes away matter, inoculates, produces 

 a sore, uneasiness in the axilla, and perhaps some affection 

 of the system. This is one way in which a fallacious idea 

 of security both in the mind of the inoculator and the patient 

 may arise ; for a disease may thus have been propagated from 

 a simple eruption only. 



One of the first objects then of this pursuit, as I have 

 observed, should be, to learn how to distinguish with ac- 

 curacy between that peculiar pustule which is the true cow 

 pock, and that which is spurious. Until experience has de- 

 termined this, we view our object through a mist. Let us, 

 for instance, suppose that the smallpox and the chicken-pox 

 were at the same time to spread among the inhabitants of a 

 country which had never been visited by either of these dis- 

 tempers, and where they were quite unknown before: what 

 confusion would arise ! The resemblance between the symp- 

 toms of the eruptive fever and between the pustules in either 

 case would be so striking that a patient who had gone through 

 the chicken-pox to any extent would feel equally easy with 

 regard to his future security from the smallpox as the person 

 who had actually passed through that disease. Time and 

 future observation would draw the line of distinction. 



So I presume it will be with the cow-pox until it is more 



