156 Life ofJ^v, Jenner. 



1799, for when detailing to Dr. Woodville a similar case, 

 he says, *< it would be unfair to draw positive conclu- 

 sions from such scanty precedents ; but yet they lead 

 one to hope, that a mild variety of the small-pox might thus 

 be actually created." The idea of a disease having fixed 

 and permanent characters, less virulent than small-pox, 

 and more obviously energetic than cow-pox, had often passed 

 through our minds, but until we read Dr. Baron, we were 

 imaware of the advance that had been made towards de- 

 termining the point. The cow-pox, however, is differently 

 circumstanced. It never produces small-pox, and small-pox 

 never produces it, at least in man ; and, therefore, it is cer- 

 tainly questionable whether these two disorders are essen- 

 tially the same ; — in other words, whether the cow-pox be a 

 permanent, as the swine-pox is a temporary, modification of 

 variola. In favour of such an opinion. Dr. Jenner appears, 

 as far as we can judge from the scattered discussions in Dr. 

 Baron's book, to rely principally on the two following argu- 

 ments: — 1. The cow-pox in the cow is not a local, but a 

 constitutional, and even sometimes a malignant disease, (p. 

 352.) 2. The cow-pox contaminated by small-pox will 

 sometimes lose its virulence, cease altogether to produce 

 eruptions, and at length become almost assimilated to the true 

 vaccine character, (p. 245.) Upon the whole, the question 

 of the identity of cow-pox and small-pox may be considered 

 as still undecided. The general voice of the profession is, 

 we think, rather against, than in favour of the doctrine. 



The straits and difficulties of this inquiry, however, lie 

 still before us. We have yet to investigate the alleged 

 connexion of cow-pox with the disorder called the grease in 

 horses. In Jenner's first essay, this subject is brought pro- 

 minently forward, and not only is the identity of the two 

 afi'ections maintained, but it is confidently stated, that the 

 cow-pox Tzezj^r occurs in dairy countries, except where there is 

 access to horses. We cannot help thinking that the great stress 

 thus laid upon the equine origin of cow-pox was somewhat in- 

 judicious. The facts bearing upon the question were then only 

 imperfectly known to Jenner. (See p. 243.) The doctrine itself 

 had no obvious connexion with the great practical truth which 

 he laboured to establish. It could not tend in any degree to 

 strengthen public faith in the virtues of the cow-pox, and it 

 certainly gave a handle to the opposers of vaccination, of 

 which they were not slow to avail themselves. It gave oc- 

 casion to endless controversies and bickerings. We are told 

 (at p. 584), that in 1803, all the principal medical men in 



