PEARSON’S _INQUIRY_.
Dr. Pearson’s _Inquiry concerning the History of the Cowpox_[105]
is a remarkable proof of the alacrity and energy with which
Jenner’s project was entertained. As observed, Jenner’s _Inquiry_
was published at the end of June, 1798, and ere six months
were over, in November, 1798, appeared Pearson’s _Inquiry_, a
masterly review of Jenner’s; and not only a review, but a record
of investigation, personal and by correspondence with country
physicians and farmers; the entire work displaying a capacity for
business to which Jenner was wholly unequal.
Cowpox did not come before Pearson as a novelty, nor Jenner in
connection therewith. He relates--
When I was in company with the late Mr. John Hunter, about
nine years ago, I heard him communicate the information he had
received from Dr. Jenner, that in Gloucestershire an infectious
disorder frequently prevailed among the milch cows, named the
Cowpox, in which there was an eruption on their teats; that those
who milked such cows were liable to be affected with pustulous
eruptions on their hands, which were also called the cowpox; that
such persons as had undergone this DISEASE COULD NOT BE INFECTED
BY THE VARIOLOUS POISON; and that as no patient had been known to
die of the Cowpox, the practice of the inoculation of the poison
of this disease, to supersede the Smallpox, might be found, on
experience, to be a great improvement in physic.
I noted these observations, and constantly related them, when on
the subject of Smallpox, in every course of lectures which I have
given since that time. (P. 5.)
The communication of Jenner to Hunter was nothing of a discovery.
There was no secret in the existence of Cowpox, nor in the belief
that inoculation therewith fortified the sufferer against Smallpox.
Dr. Pulteney, of Blandford, informed Pearson that--
Cowpox is well known in Hampshire, Dorsetshire, Somersetshire,
and Devonshire. It is not unknown in Leicestershire, and other
midland counties; but dairymen keep it a secret as much as
possible, as it is disreputable to the cleanliness of their
produce. (P. 8.)
In the northern counties and in Wales, Cowpox was either rarely
seen or unknown. In Cheshire, as much of a dairy county as
Gloucestershire, where also men acted as milkers, the disease
was never met with. Where, however, Cowpox was recognised, the
faith in its efficacy against Smallpox appeared to be general,
and inoculators regarded it as a bar to their success. Thus Mr.
Giffard, surgeon, Gillingham, wrote to Pearson, 9th August, 1798--
Cowpox is more known in Dorsetshire than in most counties. Last
winter I inoculated three parishes, and some of the subjects
told me they had had the Cowpox, and that they should not take
the Smallpox; but I desired to inoculate them, and did so two or
three times, but without effect. Persons never take the Smallpox
after they have had the Cowpox. (P. 14.)
At a milk-farm on the Hampstead Road, Pearson found a man who had
often seen Cowpox in Wiltshire and Gloucestershire. He said that--
He had known many who had had Cowpox, and they never suffered
from the Smallpox, although it prevailed in their own families.
To use his own words, they who have had the Cowpox “are hard to
take the Smallpox.” (P. 29.)
Mr. Rolph, surgeon, Peckham, who had practised in Gloucestershire,
informed Pearson that--
Cowpox was very frequently epizootic in the dairy-farms in the
spring.... A great number of instances of the Cowpox in milkers
had fallen under his observation, but not a single mortal, or
even dangerous, case occurred. There was not a medical man in
Gloucestershire, or scarce a dairy-farmer, who did not know
from his own experience, or that of others, that those who have
suffered the Cowpox are exempt from the agency of the variolous
poison. (P. 95.)
Dr. Croft likewise told Pearson--
That in Staffordshire to his knowledge, the fact had been long
known of the Cowpox, which prevails in that county, affording an
exemption of the human subjects from the Smallpox. (P. 35.)
Nor did what was so widely believed escape mention in medical
literature. Thus Dr. Beddoes, in _Queries concerning Inoculation_,
had written in 1795--
I have learnt from my own observation, and the testimony of
some old practitioners, that susceptibility to the Smallpox is
destroyed by the Cowpox, which is a malady more unpleasant than
dangerous.
And Dr. Adams, in his treatise on _Morbid Poisons_, 1795, observed--
Cowpox is a disease well known to the dairy-farmers in
Gloucestershire. What is extraordinary, as far as facts have
hitherto been ascertained, a person infected with Cowpox is
rendered insensible to the variolous poison.
And Dr. Woodville in his _History of Inoculation_, 1796, argued--
It has been conjectured that the Smallpox might have been derived
from some disease of brute animals; and, if it be true that
the mange affecting dogs, can communicate a species of itch to
man; or that a person, having received a certain disorder from
handling the teats of cows, is thereby rendered insensible to
variolous infection ever afterwards--then, indeed, the conjecture
is not improbable.
The belief, moreover, that Cowpox was good against Smallpox, had
tempted several to court the disease. The Rev. Herman Drewe wrote
to Pearson of himself and Mr. Bragge, surgeon, Axminster, 5th July,
1798--
Mr. Bragge and I endeavoured to try the experiment of inoculating
with the matter of the Cowpox, but from the scarceness of the
disease, and unwillingness of patients, we were disappointed. (P.
39.)
Mr. Dolling of Blandford related that--
Mr. Justings, of Axminster, inoculated his wife and children
with matter taken from the teats of a cow that had the Cowpox.
In about a week afterwards their arms were very much inflamed,
and the patients were so ill that the medical assistance of Mr.
Meach, of Cerne, was called for. The patients did well. They were
afterwards inoculated for the Smallpox by Mr. Trobridge without
effect. (P. 42.)
Dr. Pulteney of Blandford informed Pearson that--
A respectable practitioner inoculated seven children for the
Smallpox, five of whom had been purposely infected with the
Cowpox by being made to handle the teats and udders of cows
under the disease, and in consequence contracted the distemper.
These five, after inoculation for the Smallpox, did not sicken,
whilst the other two did. (P. 39.)
These cases were examples of many; and if it be asked, why were not
such inoculations repeated, we may take an answer from Mr. Fewster,
surgeon, of Thornbury, who, in a practice of thirty years in
Gloucestershire, inoculated thousands with Smallpox, and had known
“numberless instances of Cowpox.” He wrote, 11th October, 1798--
In general, I think, Cowpox is a much more severe disease than
the inoculated Smallpox; nor do I see any great advantage from
its inoculation. Smallpox inoculation seems to be so well
understood that there is very little need of a substitute. It is
curious, however, and may lead to other improvements. (P. 104.)
To show still further how Jenner’s communication was “in the
air” ready for descent. Mr. Downe, surgeon of Bridport, wrote to
Pearson, 1st August, 1798--
A few years ago when I inoculated a great number for the
Smallpox, I remarked that I could not by any means infect one
or two of them; and, on inquiry, I was informed that they had
previously been infected with the Cowpox. I know that a medical
man in this part of the country was injured in his practice by
a prejudice raised unjustly that _he intended to substitute the
Cowpox for the Smallpox in inoculation_. So great an enemy to
improvement are the prejudices of the public in the country, that
I think experiments of importance can only be made in hospitals.
(P. 10.)
Thus popular scandal anticipated what was called Jenner’s discovery!
Nor was Pearson content simply to inquire of others: he
experimented himself, and put Cowpox to the test a week or so
before the appearance of Jenner’s _Inquiry_. He wrote--
Happening, on the 14th of June, to be with Mr. Lucas, apothecary,
on professional business at Mr. Willan’s farm, adjoining the New
Road, Marylebone, where from 800 to 1000 milch cows are kept, I
availed myself of the opportunity to make inquiry concerning the
Cowpox. I was told it was a pretty frequent disease among the
cows of that farm, especially in winter, and that it was supposed
to arise from sudden change from poor to rich food. It was also
well known to the servants, some of whom had been affected with
the malady from milking the diseased cows. On investigation, I
found that three of the men-servants, namely, Thomas Edinburgh,
Thomas Grimshaw, and John Clarke had been affected with the
Cowpox, but not with the Smallpox. I induced them to be
inoculated for the Smallpox, and, with the view of ascertaining
the efficacy of the variolous infection employed, William Kent
and Thomas East, neither of whom had either the Cowpox or the
Smallpox, were also inoculated. (P. 14.)
The result conformed to expectation: Edinburgh, Grimshaw, and
Clarke did not take Smallpox, even though inoculation was repeated,
whilst Kent and East did. Pearson set forth his experiments much
more philosophically than Jenner, but his bias was pronounced, and
it blinded him to some obvious considerations; and it is marvellous
how easily we may accumulate details for which we have a fancy.
Summing up the testimonies he had collected, he held that--
The body of evidence is numerous and respectable, declaring
that a person who has laboured under the Cowpox fever and local
eruption, is not susceptible of the Smallpox. It does not appear
that a single well authenticated contravening instance has fallen
under observation. But I do not apprehend that accurate and able
reasoners will consider the fact as completely established,
though, I doubt not, they will allow that the testimonies now
produced greatly confirm the probability, and that the cautious
appropriation of it in practice is warrantable. (P. 64.)
In this summary we perceive the limit and imperfection of Pearson’s
_Inquiry_. Smallpox _did_ follow Cowpox: it was well known that
it did: and Dr. Ingenhousz ascertained the fact as soon as he
looked for it. Moreover Pearson showed himself ignorant of Jenner’s
position, who, recognising the fallacy of the rural superstition,
was compelled to discriminate Cowpox as genuine and spurious--the
genuine being the variety derived from Horsegrease.
Upon Jenner’s assertion that Cowpox was unaltered by transmission
from arm to arm, Pearson remarked, “The fact remained to be
proved.” That Cowpox produced a harmless ailment was not, he
thought, to be hastily assumed. Dr. William Heberden had recently
inoculated 800 poor persons at Hungerford without a mishap, and
1700 had passed through Dr. Woodville’s hands in the current
year (1798) with only two deaths; yet how erroneous would be to
argue that variolous inoculation was harmless from such special
experience!
Such instances of success can only be attributed to a certain
favourable epidemic state of the human constitution itself,
existing at particular times, for the proportion of deaths from
inoculation is usually much greater, owing, probably, to certain
unfavourable epidemic states. (P. 67.)
If Cowpox remained unchanged in transmission from arm to arm, it
would be no harmless ailment; for the evidence was distinct that it
was frequently a severe one. For example, Edinburgh told Pearson
that when suffering from Cowpox he had to give up work and go into
an hospital; and Grimshaw that the disease was uncommonly painful,
with swellings in his armpits, sore to the touch; and the servant
at Rhodes’s farm in the Hampstead Road, who had seen much Cowpox in
Wiltshire and Gloucestershire, said the milkers were sometimes so
ill that they had to keep their beds for several days, though none
ever died of the Cowpox fever. If, however, by transmission from
arm to arm, Cowpox became milder, it was not improbable that at the
same time it would lose more or less of its protective efficacy.
Pearson might have seen and added, that resistance to inoculated
Smallpox, when the constitution was in no humour for Smallpox, was
no proof that the same constitution would resist Smallpox when
epidemic, or in condition for the evolution of the disease.
Pearson likewise took objection to Jenner’s evidence (such as it
was) that it was possible to take Cowpox after Cowpox, but not
Smallpox after Cowpox; saying--
Most of professional men are extremely reluctant in yielding
assent to this statement. Some, indeed, reject it in the most
unqualified terms. That Cowpox follows Cowpox appears certain,
but that Cowpox should avert Smallpox, and not avert itself
appears incredible. (P. 44.)
Here we see Pearson on the verge of discovery of the illusion, but
with all his training and Yorkshire shrewdness he lost the scent,
and allowed himself to be deceived; and not only deceived, but to
become a prime mover in the deception of the world. Jenner felt the
difficulty and replied--
CHELTENHAM, _27th September, 1798_.
MY DEAR SIR,--You may be assured that a person may be repeatedly
affected, both locally and generally, by the Cowpox, two
instances of which I have adduced, and have many more in my
recollection; but, nevertheless, I have some reason to suspect
that my discriminations have not been, till lately, sufficiently
nice.... Certain it is, that the skin is always subject to the
ulcerative effects of the virus; but whether the constitution can
repeatedly feel the primary effects of it, I have experiments in
view to determine. (P. 99.)
This passage is commended to those who hold with Mr. John Simon
that Jenner delivered to the world “a Master-piece of Medical
Induction,” the fruit of thirty years of incessant thought,
watching and experiment. It is plain that in 1798 the very elements
of the problem were by him undetermined, and the most obvious
objections unforeseen and unconsidered.
Pearson’s strongest opposition was reserved for the asserted origin
of Cowpox in Horsegrease. He said--
It has no better support than the coincidence in some instances
of the two diseases in the same farm in which the same servants
are employed among the Horses and Cows.
I have found that in many farms the Cowpox breaks out although no
new-comer has been introduced to the herd; although the milkers
do not come in contact with the Horses; although there are no
greased Horses; and even although there are no Horses kept on the
farm.
It appears that the Cowpox does not break out under the most
favourable circumstances, if it be occasioned by _the Grease_.
“I have had,” writes Sir Isaac Pennington, Cambridge, 14th
September, 1798, “Dr. Jenner’s book some weeks, and the
particulars stated in it are really astonishing. I have made
inquiries upon the subject at Cottenham and Willingham, in which
two parishes 3000 milch Cows are kept; also a great many Horses
of the rough-legged cart kind (much liable to the scratches or
grease) half the parishes being under the plough, and the men
much employed in milking. But I cannot find that any pustulous
eruptions on the teats of the Cows, or on the hands of the
milkers, have ever been heard of.” (P. 82.)
In the opening of his _Inquiry_, Pearson was good enough to say of
Jenner, “I would not pluck a sprig of laurel from the wreath that
decorates his brow”; but, disputing the origin of genuine Cowpox in
Horsegrease, he might have asked himself, what sprig of laurel he
had left. That Cowpox originated in Horsegrease was not Jenner’s
discovery. As Pearson ascertained in the London milk farms, “There
was such a notion entertained in several parts of the country,
whatever might be its foundation.” (P. 86.) But the definition of
Horsegrease Cowpox as the form of Cowpox that justified the faith
of the country-folk in the power of the disease to avert Smallpox,
was Jenner’s solitary distinction--the principle and motive of
his _Inquiry_, which, to prove fallacious, was to extinguish his
title to regard. Cowpox apart from Horsegrease was clearly taught
by Jenner to have no influence on the constitution, and to be
attended with no erysipelas. “Let me call your attention,” he wrote
to Pearson, 27th September, 1798, “to a similarity between the
Smallpox and the Cowpox when inoculated. The symptoms of absorption
first disturb the system, and, secondly, the system feels the
consequences of the local sores. Exactly so with the Cowpox; and
_as the Cowpox inflammation is always of the erysipelatous kind_,
when it spreads over the skin to any great extent, it produces
symptoms not unlike the confluent Smallpox.” (P. 100.)
Pearson foresaw that if the principle of inoculation with Cowpox
were established it would lead to other applications--
The Cow Poison appears to alter the human constitution, so as to
render it insusceptible of a different morbific poison, namely,
the variolous in producing the Smallpox. This fact is, I believe,
quite a novelty in physiology and pathology: it indicates a new
principle in the mode of prophylactic practice. And we now see a
principle upon which diseases from various other morbific poisons
may possibly be prevented from taking place, such as the Measles,
Ulcerous Sore Throat, Hooping Cough, Syphilis, etc., namely, in
consequence of destroying the excitability of the constitution
to such poisons by the agency of different, and perhaps less
hurtful ones. Whether the Cowpox preserves the constitution from
other morbific poisons, besides the variolous, is an undecided
question. (P. 79.)
Like Jenner, he also recognised in Cowpox a counter-irritant--a
safe sort of fever that might be used to drive off other diseases--
If it be true that the same constitution is liable to undergo
repeatedly the Cowpox, to which distemper no one has fallen a
victim, practitioners may avail themselves of this means of
exciting an innocent fever as a remedy of various disorders; it
being a truth, admitted by men of experience, that fevers are
occasionally efficacious remedies, especially for inveterate
chronic maladies, such as Epilepsy, Hysteria, Insanity, St.
Vitus’s Dance, Tetanus, skin deformities and diseases, etc. (P.
81.)
Nor was the notion without warrant, for Smallpox itself was
credited with a double action as a generator and exterminator of
disease--
A disposition to certain diseases, and even diseases themselves,
are not rarely brought on by the Smallpox; but sometimes also
dispositions to diseases, and diseases themselves of the most
inveterate kind are removed by the Smallpox. (P. 77.)
In one respect, Jenner showed himself superior to Pearson, namely,
in offering some explanation of Cowpox. Pearson accepted the
disease on the rural terms--as an eruption on Cows attended with
no serious illness. If in any way such Pox was equivalent to
Smallpox, it was inexplicable that it should be limited to the
udder and teats of milch cattle, and that males, and females not in
milk, should be exempt from infection. A disease so unique wanted
accounting for; but Pearson made no attempt to account for it,
nor gave any sign that he apprehended the difficulty. Jenner, on
the other hand, accounted for Pox on the Cow by referring it to
infection from the Horse conveyed by the milkers, which explanation
Pearson rejected. But in giving Jenner credit for so much, let
it not be for over much. Whilst he ascribed Cowpox to a credible
cause, he did not recognise his advantage and summon gainsayers
to explain how Cowpox, as described by them, could exist without
Bullpox. On the contrary, as we shall see, Jenner submitted to be
silenced on this point for reasons far from creditable.
FOOTNOTE:
[105] _An Inquiry concerning the History of the Cowpox, principally
with a view to supersede and extinguish the Smallpox._ By George
Pearson, M.D., F.R.S., Physician to St. George’s Hospital, etc.
London, 1798, 8vo., pp. 116.