Life of Dr. Jenner. 161 



we have already shown to be at least questionable. That it 

 is inapplicable upon a great scale is obvious, from the vast 

 disproportion between the cases of recurring small-pox, and 

 of small-pox after vaccination. Jenner was himself so 

 sensible of this, that, subsequent to the period comprised in 

 Dr. Baron's volume, he enlarged the theory of imperfect 

 vaccination, and admitted, as a fourth principle, diminishing 

 the influence of vaccination, pre-occupation of the skin, by 

 herpetic or other eruptions, during the progress of the cow- 

 pox. We are warranted by his own words * in stating, 

 that he attributed very great importance to this very pa- 

 thological doctrine. He calls it the grand impediment, and 

 expresses his pleasure that continental nations now begin to 

 estimate its influence." 



Such are the views taken by Dr. Jenner, of the causes of 

 vaccine failure. We should close the argument here, if we 

 were not desirous to say a few words on an hypothesis which 

 is often brought forward in common conversation as capable 

 of explaining, in a great degree, the occurrence of small«pox 

 after vaccination. We mean deterioration of the virus from 

 passing through so many successive bodies ; and the remedy 

 proposed, is, of course, more frequent recurrence to the cow. 

 This idea, we believe, was never countenanced by Dr. Jenner, 

 and it is not generally adopted by medical men. It appears 

 to us altogether unworthy of credit ; for, first, some of those 

 who were vaccinated by Jenner himself, in the very infancy 

 of the practice, have since taken small-pox. The first lady 

 of rank who was vaccinated in this country (the present 

 Countess of Denbigh) had small-pox after vaccination, very 

 favourably, in 1822. A son of Admiral Barclay, the steady 

 friend and supporter of Jenner, vaccinated in 1806, to the 

 perfect satisfaction of Dr. Jenner, had small-pox also in 

 1822, somewhat more severely, but not at all dangerously. 

 2. Those who take cow-pox naturally, or direct from the 

 cow, are still sometimes attacked by small-pox. 3. It is 

 contrary to the analogy of small-pox, which is as virulent 

 now, as it was in the days of Rhazes and Avicenna. 4. We 

 have strong grounds for suspecting, that the cow-pox, in- 

 stead of deteriorating in quality by successive inoculations, 

 actually improves ; of this, at least, we are sure, that by 

 careful selection of healthy subjects, a pock comes at length 

 to be formed, which passes through its stages with a regu- 

 larity and beauty most gratifying to witness. But we must 



* See Lond. Med. and Phys. Jguinal, for September, 1822. vol. 48. p. 194. 

 JAN.— MARCH, 182r. M 



