I N O C U 
through the brute animal. Tbe experiment has often 
been tried in many parts of the world. A local pultule 
has fometimes been excited ; but the matter which it 
yielded has not fucceeded in fubfequent inoculations. 
Were the cow-pox thus communicated to the cows, it 
would be as common in Chelhire as in Gloucefterlhire, as 
common in Scotland or France as in England, and as 
common in Alia or America as in Europe. As an addi¬ 
tional proof that it is not thus produced, it will be fuffi- 
cient to Hate the information received from Mr. Dalton, 
a furgeon at Madras. After obferving, that he had not 
been able to procure genuine matter in India, in order to 
make experiments, or even to learn that horfes in India 
are fubject to the greafe, he gives the refult of repeated 
experiments which he made in the government-gardens 
at Madras, by order of the governor, earl Powis, and in 
his prefence. To render thefe experiments as complete 
and fatisfaftory as poffible, feveral milch-cows were fe- 
lefted ; and fome of them were inoculated by Mr. Dalton, 
in their teats and udders, with the moll aftive variolous 
matter; while the teats of others were rubbed with it for 
a confiderable time, till they became highly inflamed. 
No puftule was excited in any one of them ; but ulcera¬ 
tions appeared on thofe teats, into which matter had been 
rubbed, the third day after the fridtion. Several young 
' children were inoculated with the matter thus produced, 
and their arms inflamed and feltered. They had alfo a 
flight degree of fever, which gave Mr. Dalton hopes that 
bis experiment had fucceeded, and that he had generated 
a mild fp'ecies of finall-pox ; but, on putting them to the 
left of variolous inoculation, they all had the fmall-pox 
in the moft indubitable manner, and regularly went 
through the difeafe. Mr. Dalton concludes with remark¬ 
ing, that all thefe circumftances will bear the ftrifteft 
fcrutiny; as they are well known to feveral medical prac¬ 
titioners at Madras. 
‘ It has been juftlv obferved, that, for the difcovery of 
this excellent art, we are indebted, under Providence, to 
a fortunate concurrence of circumftances : firft, to the ta¬ 
lents of Dr. Jenner; fecondly, to his education under the 
celebrated Hunter; and thirdly, to his fituation in the 
vale of Gloucefter. His inquiry into the nature of the 
cow-pox commenced about the year 1776. His attention 
to this Angular difeafe was firft excited by obferving, that, 
among thofe whom he inoculated for the fmall-pox, 
many were infufceptible of that diforder. Thefe perfons, 
lie was informed, had undergone the cafual cow-pox, 
which had been known in the dairies from time imme¬ 
morial ; and a vague opinion had prevailed, that it was 
a preventive of the fmall-pox. 
He met with many apparent exceptions to this ryle ; 
which led him to alk the opinions of other medical prac¬ 
titioners in the neighbourhood, who all agreed, that the 
prophylactic power of the cow-pox was not to be relied 
on. This for a while damped, but did not extinguilh, 
his ardour ; for he had the fatisfaftion to learn, that the 
cow was fubjeft to various eruptions, called by that 
name, all of which were capable of infecting the hands 
of the milkers. Having furmounted this obftacle, he 
formed a diftinftion between the different kinds of puf- 
tular eruptions, to which the cow is liable ; denominat¬ 
ing one fpecies the true, and all the others the fpurious, 
cow-pox This impediment to his progrefs was not long 
removed, before another, of far greater magnitude in ap¬ 
pearance, ftarted up. Inftances were not wanting to 
prove, that, when the genuine cow-pox broke out in a 
dairy, fome perfons who had experienced the difeafe re¬ 
filled the fmall-pox, and others continued fufceptible of 
that diftemper. This obftacle, as well as the former, 
gave a painful check to his fond afpiring hopes ; but re¬ 
flecting that the -operations of nature are for the moll 
part uniform, and that, when two perfons have had the 
cow-pox, it is not probable one Ihould be perfectly 
Ihielded from the fmall-pox, and the conftitution of the 
other remain unprotected, he refumed his labours with 
, A T I O N. 99 
redoubled ardour. The refult was fortunate ; for he now 
difcovered, that vaccine as well as variolous matter un¬ 
dergoes a change ; and that, when it has loll its fpecific 
property, it is Hill capable of producing a pultulous 
eruption. Hence, a perfon who milks a cow* one day 
may receive the infection of the genuine cow-pox, and be 
rendered forever fecure from the infection of the fmall- 
pox; while another, who milks the fame cow the next 
day, may have a puftulous eruption, and perhaps a con- 
ftitutional indifpofition to a confiderable extent, yet Hill 
remain fufceptible of the variolous contagion. 
While thus invelligating the nature of the cow-pox, 
he was ftruck with the idea, that it might be practicable 
to propagate the difeafe by inoculation, after the manner 
of the finall-pox ; firft, from the cow, and then from one 
human fubjeCt to another. The firft cafe in which he put 
his theory to the tell infpired him with confidence ; and 
a regular feries of experiments, which he afterwards inlti- 
tuted for that purpofe, was crowned with fuccefs. Seve¬ 
ral perfons were fuccefliveVy inoculated from each other 
with vaccine matter, and afterwards expofed, in a variety 
of way9, to the inreftion of the fmall-pox, which they 
all refilled. 
This difcbvery was communicated to the world by Dr„ 
Jenner, in a treatife publilhed in June 1798, entitled, “ Aa 
Inquiry into the Caufes and EffeCls of the Variol# Vac- 
cirue, a Difeafe difcovered in fome of the weitern Counties 
of England, particularly Gloucefterlhire, and known by 
the name of the Cow-pox.” The refult of his further 
experience was alfo brought forward in fubfequent pub¬ 
lications, in the courfe of the two fucceeding years; and 
the whole work has been fince republifhed in one volume. 
He has alfo written a fmall traCl, entitled, The Origin of 
Vaccine Inoculation ; from which the preceding account 
of this moft lingular improvement of the healing art, is, 
in a great meafure, extradited. 
In July 1798, Mr. Cline inoculated a child with vac¬ 
cine virus received from Dr. Jenner; which fucceeded. 
He' afterwards put the child to the tell of inoculation 
with fmall-pox matter in three places; which he refitted. 
On this occafion, Mr. Cline informs Dr. Jenner, that Dr. 
Lifter, formerly phyfician of the Small-pox Holpital, and 
himfelf, are convinced of the efficacy of the cotv-pox 5 
and that the fubftitution of this mild difeafe for the fmall- 
pox promifes to be one of the greatell improvements 
ever made in medicine. He adds, “the more I think on 
the fubjeft, the more I am imprefl'ed w ith its. importance.’" 
This inllance of the firft introduction of vaccine inocula¬ 
tion into the metropolis, it was neceflary to mention ; 
becaufe another medical praftitioner has laid claim to that 
honour. Attempts were made by Mr. Cline to conti¬ 
nue the praftice, by vaccinating other fubjefts with the 
virus thus produced; but they proved abortive; probably 
from the matter not being taken at an early period of the 
difeafe. 
In November 1798, Dr. Pearfon publilhed his “Inquiry 
concerning the Hiltory of the Cow-pox, principally with 
a view to fuperfede and extinguilh the Small-pox.” In, 
this work he brings forward the refult of an extenfive cor- 
refpondence with medical praftitioners, and others, in¬ 
different parts of the kingdom; tending to confirm Dr- 
Jenner's opinion, that the cow-pox is a preventive of the 
linall-pox. He had been informed of this difcovery of 
Dr. Jenner by Mr. Hunter, nine years before ; and had 
conllantly mentioned the circumftance, in every courfe of 
his leftures, from that time. The faft had been men¬ 
tioned in three publications ; by Dr. Adams, in his Trea¬ 
tife on Morbid Poifons; in 1795, and by Dr. Woodville, v 
in his “ Hiltory of Inoculation,” in 1796^ having been 
communicated to them by Mr. Cline, and to him by Dr. 
Jenner. It had alfo been mentioned by Dr. Beddoes, in 
1795, in his “Queries concerning Inoculation,” in a let¬ 
ter from Mr. Rolph, who was acquainted with Dr, 
Jenner. 
Information concerning the prophylaftic property of 
the 
