INOCU) 
that kind which jenner Cal’s the fpurious cow-pox; I de¬ 
termined, therefore, to decide the matter by experiment. 
A confiderable number of experiments, all uniform in 
their fymptoms and progrefs, and always conftant in their 
refdlts, put the matter beyond doubt, and gave me full 
conviition that this was the true cow-pox.” See the Plate, 
fig. i. 
We (hall immediately proceed to explain the mode of 
communicating this difeale to the human fubjecf. The 
following inftru&ions for the practice are taken from 
Ring’s Compendium. Cow-pox matter may be taken 
at any period, from the firth appearance of the veficle, till 
the areola begins to form, by final! punftures ; allowing 
it time to flow; or promoting the difcharge by gentle 
preflu re with the lancet. It muft be taken with great 
caution ; otherwile the intention of the inoculator may 
be fruftrated, or violent inflammation and ulceration of 
the arm may enfue. The cow-pox matter is to he in- 
ferted, by a fuperficial punfture, into the middle of the 
arm, between the fboulder and the elbow; or, when the 
arm is .likely to be much ufed, into the infide of the leg. 
Fluid matter is preferable to dry ; but thofe inoculators 
who have not a conltant fucceflion of patients, and can¬ 
not readily procure a f'refli fuppiy of matter, fliould pre- 
ferve it-on vaccinators for future occaflons. In this man¬ 
ner, when kept in a cool place, it may be preferved feve- 
ral months. Cow-pox matter may be preferved, and 
conveyed, on the point of a vaccinator ; that is, a bit of 
ivory, fhaped like the tooth of a comb, and pointed like 
a lancet. When'the matter is intended to be fent to a 
diftant place, or to be kept long, the vaccinator fliould be 
charged feveral times. It fliould not be dried before the 
fire; and, when luffered to dry on a lancet, fliould not 
be kept above two or three days. When dry matter is 
ufed, it fliould not be moiftened previoufly to inlertion ; 
but, the longer it has been kept, the longer the point of 
the inftrument ought to remain under the cuticle, that it 
may have time to diflolve. When fluid matter is ufed, the 
lancet fliould be waffled in cold water, and wiped dry after 
every purnflure. Various other methods have been con¬ 
trived for the prefervation and conveyance of cow-pox 
matter; but the ivory lancet, invented by Dr. de Carro, and 
the vaccinator above-defcribed, invented by Mr. Ring, 
which is generally confidered an improvement of it, being 
much cheaper and more portable, are now commonly pre¬ 
ferred. When vaccinators are to be fent to a moderate dif- 
tance, they may be wrapped in paper; but, when they are to 
be fent to a great diltance, they may be inclofed in a quill, 
to be flopped with white wax. Sealing-wax is not proper for 
this purpofe; becaufe it cannot be employed without 
heat, which is extremely prejudicial to the matter. When 
a vaccinator is to be ufed for inoculation, a final 1 oblique 
pundture is firft to be made with a lancet; then the point 
of the vaccinator is to be inferted, and held in the punc¬ 
ture fome .time, and afterwards repeatedly wiped on the 
part; in order to in lure, if poflible, the lodgment of the 
matter. When the patient relides atadiftance, oris in danger 
of catching the fmall-pox, it is proper to inoculate in both 
arms. Another reafon for inoculating in both arms is, 
that a more copious fuppiy of matter is thus afforded for 
future inoculation. 
Thofe who have been expofed to the infection of the 
fmall-pox, ought to be inoculated with the cow-pock ; 
which feldom fails tofuperfede, or mitigate, the fmall-pox. 
Vaccination may be accounted perfect, when recent 
lymph has been carefully im'erted beneath the cuticle in 
a perfon free from any contagious diforder, and has pro¬ 
duced a femi-tranfparent pearl-coloured veficle, which, af¬ 
ter the ninth day, is furrounded by a red areola, and af¬ 
terwards terminates in a hard dark-coloured fcab. The 
form and ftrufture of this veficle is peculiar. Its bale is 
circular, or fomewhat oval, with a diameter of about four 
lines on the tenth day ; fee the plate, fig. a. Til! the end 
of the eighth 'day, its upper furface is uneven, being c en¬ 
voi. XI. No. 737. 
, A T I O N, - 101 
fiderably more elevated at the margin than about the cen¬ 
tre, and fometimes indented by one or two concentric 
furrows; but on the ninth or tenth day the furface be¬ 
comes plane, and in a very few inftances the central part 
is higheft. The margin is turgid, firm, fhfl.ing, and 
rounded, fo as often to extend a little beyond the line of 
the bafe, as fhown at fig. 3. The veficle confilts inter¬ 
nally of numerous little cells, filled with clear lymph, and 
communicating with each other. The areola, which is 
formed round the veficle, is of an intenie red colour. Its 
diameter differs in different perfons from a quarter of.an 
inch to two inches, and it is ufually attended with a con¬ 
fiderable tumour and hardnefs of the adjoining cellular 
membrane. On the eleventh and twelfth day, as the are¬ 
ola declines, the furface of the veficle becomes brown in 
the centre, and lefs clear at the margin, as fhown at fig. 4. 
The cuticle then begins to feparate, and the fluid in the 
cells gradually concretes into a hard rounded fcab of a 
reddifh-brown colour. This fcab becomes at length 
black, contracted, and dry, but it is not detached till af¬ 
ter the twentieth day from the inoculation. It leaves a 
permanent circular cicatrix, about five lines in diameter, 
and a little deprefled, the furface being marked with very 
minute pits or indentations, denoting the number of cells 
of which the veficle had been cornpofed. 
The figns of infeflion (fays Dr. Pearfon) are generally 
evident on the arm on the third day; but in one instance, 
the marks of the puncture difappeared, and 1 concluded 
that the inoculation had failed. On the tenth day,being 
defired to vifit the child, I found the inoculated part be¬ 
ginning to inflame, and it palled through its feveral ftages 
with regularity. In another inftance, where the inocula¬ 
tion was performed by a gentleman who aflilted me at the 
Difpenfary, in Carey-ftreet, the inflammation did Hot 
commence till the twentieth day after the infertion of the 
fluid. 
During the progrefs of the veficle fome diforder takes 
place in the conflitution, and there is frequently on the 
arms and back a papulous eruption refembling fome forms 
of the lichen and ftrophulus. Thefe circumfiances we 
fliould by analogy judge defirable ; but they do not al¬ 
ways occur, nor are they deemed requifite to enfure the 
full effeft of vaccine inoculation.' One of thefe papulous 
eruptions is fhown at fig. 5. 
The inoculation of vaccina is an operation of more de¬ 
licacy than was at firft fufpefted, and fliould never be con¬ 
fidered as fafe, except under the almoft daily -infpeftion. 
of a man of experience. The virus is eafily deteriorated, 
and then becomes a common poifon, capable of producing 
a foul fore, an axillary tumour, fever, and its confe- 
quences. The fame changes appear to have taken place 
in a lefs degree at an advanced period of the difeafe ; and, 
though we have the teftiinony of very refpectable authors 
that it fucceeds from the tenth to the twelfth day, it 
fliould generally be taken before that period. It is in¬ 
jured by even a flight degree of heat, fo as to be in dan¬ 
ger from the burning wax with which the packets arc 
iealed, and very certainly by being carried in the breeches 
pocket. To be certain of fuccefs, the child, from whom 
it is to be taken, fliould be prefent, and the cuticle raifed. 
by a clean lancet before introducing the infefted one. If 
on glafs, it fliould be diluted in the minuteft drop of cold 
water, and mixed by the point of the lancet itfelf. By 
thefe precautions failure is very uncommon. 
We may add to thefe remarks, that, in a few very rare 
inftances, the fever, though fliort, has been fmart, and that, 
in children Tubjeft to convulfions, a fit has fometimes oc¬ 
curred. But we have feldom heard of the flighteft ap¬ 
pearance of danger. It is of more confequence to notice 
the fymptoms of imperfect vaccination, and we fhall em¬ 
ploy the authority of Dr. Willan. 
“Vaccination is imperfefl, or infufficient, 1. When the 
fluid employed has loft fome of its original properties. 
2. When the perfons inoculated are fooh afterwards af- 
P 4 fefted 
