Life of Dr. Jenner. 157 



London were adverse to the opinion. Later observations 

 have, indeed, established the identity of the grease and the 

 cow-pox, but they have shewn, at the same time, the in- 

 correctness of some of Jenner's first ideas on the subject. 

 The following extract of a letter from Dr. De Carro, of 

 Vienna, to Dr. Monro of Edinburgh, written in 1825, (to 

 be found in the Edinburgh Journal of Medical Science), 

 may be quoted as a fair illustration of the importance of the 

 doctrine, and of the improved notions concerning it. *' The 

 source of our cow-pox (at Vienna) says Dr. De Carro, is 

 partly British, and partly originating from the grease of a 

 horse at Milan, without any intervention of a cow. The 

 efiect was so similar in every respect, that they were soon 

 mixed ; — that is to say, it was impossible to tell, after sev^eral 

 generations, and in the hands of innumerable practitioners, 

 what was equine and what was vaccine. The whole British 

 settlements in India have been equinated ; for the first liquid 

 drop which I sent twenty-five years ago to India was the 

 second generation of Milanese equine or greasy matter, 

 transplanted at Vienna. You know, by frequent reports 

 from the East, that the practice there is upon the best foot- 

 ing.'* But we fear we shall tire our readers if we prosecute 

 further the alleged connexion of human and epizootic ma- 

 ladies. We shall pass on, therefore, to another subject. 



3. In several parts of Dr. Baron's work, the doctrine is 

 taught, that cow-pox possesses powers adequate to the com- 

 plete extirpation of small-pox from the face of the earth. 

 VVe have already given an extract from the earlier writings 

 of Jenner, in which this sentiment is strongly expressed. We 

 may point out one or two other passages in which the same 

 thing occurs. Dr. Jenner's petition to the house of com- 

 mons, in the year 1802, contains the following paragraph : — 

 *' The said inoculation hath already checked the progress of 

 the small-pox, and, from its Jiature, must finally eradicate 

 that dreadful disorder."" Dr. Baron, in p. 259, has the fal- 

 lowing remark: *' But the property, of all others, which 

 peculiarly distinguishes the variolse vaccinae from small-pox, 

 and which would enable us to banish the disease entirely^ is, 

 that they are not communicable by effluvia." This notion 

 very naturally made a strong impression upon the public 

 mind, and contributed, in no small degree, to encourage that 

 ardour in the cause of vaccination which was so honourable 

 to the country. We cannot, however, on the grounds of 

 physiology, or of plain common sense, understand how such 

 an eyeut could be brought about by the means suggested. 



