27- Original Vaccine Pock Institution. 



various practitioners living in those situations, no one* had 

 taken the small-pox. 



" It will be proper to bring forward another body of evi- 

 dence different from the preceding. From its commence- 

 ment this institution has been the appointed office for sup- 

 plying weekly the army, the navy, and ordnance department 

 with vaccine matter ; yet this constant intercourse has not 

 afforded any authentic cases of failure which can be recol- 

 lected — as far as known, the reported ones appeared on in- 

 vestigation to be either misrepresentations or could not be 

 proved. 



" It must not be concealed, however, that from time to 

 time cases were made known, in the practice elsewhere, of 

 the occurrence of small-pox subsequently to the cow-pock ; 

 which, according to the evidence, we could not justly re- 

 ject, although conviction was not always felt that the case 

 was one of real small-pox after the authentic vaccina. 



" In the mean lime numerous trials were made at this 

 institution of opposing variolous and vaccine matter to each 

 other in various situations, which demonstrate the anti- 

 variolous power of the latter. These experiments cannot 

 be here detailed, but they are recorded in our minute-book 

 as materials for continuing the investigation of the laws f of 

 agency of vaccine matter. 



" At this institution, by a great number of trials, two 

 laws, first asserted in 1799> seem to have been fully con- 

 firmed, which may be considered as demonstrative of the 

 power of the vaccine affection, if duly excited, to induce 

 insusceptibility of the sma!!-pox. The laws alluded to are, 

 I. That the human constitution is incapable of undergoing 

 the vaccine affection a second time, if by the first it has 

 been rendered unsusceptible of the small-pox. 2. That the 

 human constitution is incapable of undergoing the vaccine 



* A failure has bf en lately reported to the writer of this paper, but there 

 iir.s been no opportunity to ascertain the fact by legal evidence. 



■j- The Or<;iiuil J Vacci!ie Pock Institution has published one Report of the 

 progress of this investigation, which with the proj . ent ones, pro- 



bably, will ultimately establish principles fur secure practice. .S>-e " The Re- 

 port on the Cow-Pock Itidci&ticn, Sec. ciurn ._ 1800, 1801-2, &c. by the 

 Physicians to the Institution," 8vo. 18U:i — Reynel!. 



infection 



