CHAPTER IV.
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.