SecGnd Letter to Mr. Tilloch on the Coiv-Pock. l.'ji 



two of my own children, and tolerably correctly clurac- 

 terize the usual stagc^ of the cow-pock. 



The cow -pock pustule is distintruished from the small- 

 pox pustule from the following diftercnccs : 



In the smiill-pox the inoculated pustule is angulatcd, and 

 numerous pustules surround it; in the coit'-pock, tht pustule 

 has its edges regularly circumscribed, and stands solitary; 

 the small-pox pustule contains first a fluid, then opaque 

 matter; the cow-pock pustule a gelatinous fluid, which never 

 becomes converted into pus ; the edges of the 07Zf are more 

 elevated, in the other more depressed; the scab is also much 

 darker and harder in the cow-pock. — (Jeriner.) 



The fluid of the cow-pock is like the juice of an orange, in 

 blebs; of the small-por, in a single cavity. The ouema.y be 

 inoculated upon, and is the disease of animals; whereas the 

 small-pox steins peculiar to the human race, and can be en- 

 grafted, as John Hunter's experiment proves, upon no animal. 



When the cow-pock is inoculated, it never produces anir- 

 ruptive disease likethe other, but usuallyonlyalocal pustule. 



Dr. Woodville, in his public report on the cow-pock, 

 observes, " That of the last two thousand cases of cow-pock 

 vmder my care, not a single alarming symptom was excited ; 

 and I may now add, that during the last eight months I 

 have not met with one instance of the vaccine disease, 

 which has not been as favourable as the mildest cases of 

 variolous inoculation. I have no doubt, therefore, that the 

 inoculated cow-pock is as m/ich milder than the inoculated 

 Bmall-pox, as the latter disease is milder than the casual 

 small-pox: nay, it seems to me from the very benign form 

 in which the vaccine pock has of late invariably appeared, 

 that it may be considered as a disease perfectly harmless in 

 its effects." 



Dr. Willan, in his general report of the diseases of Lon- 

 don, savs, " Few or none of the out-patients of the hospi- 

 tal, inoculated with the vaccine pock, have pustules over 

 the body." Dr. Woodville likewise observes, (Observations 

 on the Cow-Pock, page 24,) " In my private practice of in- 

 oculation for the cow-pock, which has been very extensive, I 

 have not met with one instance in wliich any pustules, re- 

 sembling those of the small-pox, appeared." My own ex- 

 perience coincides pcifectly with this statement, in dif- 

 ferent families I have sei'U inoculated with vaccine fluid, oc- 

 casionally selected by myself at the hospital, and taken on 

 new lancets, about sixlv persons, none of whom had pus- 

 tular eruptions*, at the maturation of the pock forn^cd by 



the 



* In out child, ihrtc m!mite hard tubercles appeared on th« fore-arm 

 K 4 * ii'jout 



