312 Trogrefs of the Vaccine Inoculation.^ unci 



or 30, we muft therefore conclude that the conta£l of two 

 pietals of a different kind with moift conductors, without 

 the mutual contaft of thefe metals themfelves, (which is 

 wanting in the fixth experiment, where brafs is in contaft 

 wth brals, and tin with tin,) produces nothing or almoft 

 nothing; and that, on the contrary, the mutual contact of 

 the two metals of a different kind, which ta' es place in 

 the fifth experiment, produces the whole, or almoft the 

 whole, effeft. 



XVII. A Statement of the Progrefs in ^ie Vaccine Inocula- 

 tion ; aTid Experiments to determine fome important Fa£ii 

 helonging to the Vaccine Difeafe. By George Pear- 

 son, M.D. F.R.S. Phyjician to St. George's Hof/ital, &c. 



A HE colleftion of teftlmonies which I publiflied, in No- 

 vember laft, in my Inquiry concerning the Hijiory of the Cow- 

 pox ; and the Circular Letter, which I iffaed in March, 

 fiating the progrefs of the Vaccine Inoculation, and contain- 

 ing thread impregnated with matter, have procured me much 

 information. In particular, through the recommendation of 

 the Surgeon- general^ Thomas Keate, Efq. the new practice 

 has been introduced into the army ; of which a valuable re- 

 port has been already communicated. I have been alfo fo 

 fortunate as to obtain permiffion to praftife the new inocula- 

 tion in certain fituations wher? great numbers would have 

 been inoculated for the fmall-pox. The cafes from thefe 

 fources, and a pretty large flock from private praftice, form 

 a valuable body of evidence, by means of which the profef- 

 fional public will be enabled to eftimate (I do not fay pre- 

 cifely) the value of the new praSiice ; and alfo anfwer many 

 of the queries, and fupply ibme of the deficient parts of the 

 hiftory of the vaccine difeafe, which were ftated in the In- 

 quiry above mentioned. But fuch are my occupations at 

 prefent, and in all likelihood fuch they will be for a^ confi- 

 derable time, that I cannot at this time arrange, for the ufe of 



thp 



