excellent state of health. M. Maunoir, of Geneva, on this occasion adds another instance: a child, whose arm was covered with dartrous eruptions, which inflamed during the influence of the cow-pox inoculation, and assumed the appearance of as many cow-pocks. After the vaccination was over this child got quit of the eruption entirely. The same person affirms that he has observed, even after false vaccination, a sensible improvement in the health of delicate infants.

Similar results have been announced in the Spanish expedition, with an intention to publish

them.

Dr. Sacco, in his treatise Della Vaccinazione (Milan, 1809), affirms, that when vaccinating infants affected with palsy in the arms or lower extremities, troubled with chronic diseases of the glands, &c. he made a great number of punctures on purpose, to the amount of thirty or forty: that some of these patients were perfectly cured, and that the health of others was considerably im proved.

M. Barrey, of Besançon, observes that vaccination had been performed, in 1804, in three villages belonging to his department, on 141 infants under twelve years of age, constituting more than one half of all the children under that age in the place. In 1809 no fewer than 134 of these children enjoyed perfect health, seven alone having died of different diseases; but of the children that had not been vaccinated no fewer than forty-six were dead, though no small-pox had visited the country during the period. If under this last number be only included the children that existed in 1804, and not those born between that period and 1809, we must conclude that vaccination had rendered the children less susceptible of other diseases; but M. Barrey's observation is not sufficiently precise to enable us to estimate its importance.

The facts contained in the correspondence of Paris present themselves in a much greater number. If we refuse to admit all these cures to be owing to vaccination, we shall at least allow the coincidence of the cures with vaccination. Even in that case the great number of facts must produce at least a suspicion that vaccination had a useful effect in these cases, and give us a cer tainty that at least it was not injurious.

The names of the observers, the places where the observations were made, the kind of observations, are marked with precision in the notes which have been put into our hands. A considerable number enter into details, both respect ing the phenomena and the methods employed; the number of punctures made in order to induce a more considerable commotion, and to render it more general and more efficacious.

We ought to remark here more particularly the maladies which affect the organs and functions which belong to the lymphatic system. On that account we shall begin with them. Fourteen observers have given a great number of examples of the crusta lactea disappearing after vaccina. tion; sometimes after a suppuration of the cowpox continued for twenty-seven days. Seven observers have sent a great number of observa tions, two of which are accompanied with details, stating the termination of dartrous affections spread over different parts of the body, and especially the arms, after vaccination. In one of these cases the cure was preceded by a violent inflammation round the cow-pox, and by a suppuration kept up for a month, Eighteen ob VOL. XI.-PART II,

servers have given an account of chronic and obstinate opthalmias in scrofulous children cured by vaccination. Eight of these observations are detailed. In several cases the punctures made amounted to fifteen or twenty. Some were made in the nape of the neck. In most of them the suppurations were long continued; sometimes they were succeeded by blisters: but in every one of the cases the same means had been employed before vaccination without any effect. Twelve observers have given numerous facts relative to the termination of scrofula after vaccination. Eight of these are detailed. In one the scrofula was complicated with opthalmia. Sixteen punctures were made in the limbs. On the seventh day the child opened its eyes, and was capable of bearing the light. The inflammation of the punctures was violent: the inguinal glands subsided, the scrofulous tumours disappeared, and the cure was complete; but it was thought proper to endeavour to render it still more secure by a cautery performed on one of the limbs. In another case the scrofulous tumours were open, they discharged an unhealthy pus, and the flesh was pale and fungous. During the progress of the cow-pox the edges of the ulcers became red, and the flesh firm; the suppuration became less abun→ dant, and less watery; much of the humours was drawn to the vaccinated arm; the scrofulous tumours healed in the course of a month; the cowpox continued to suppurate during three months, and then the cure was complete.

Since the introduction of vaccination into the department of Mount Blanc, M. Caron, physician of Annecy, affirms that the number of scrofulous diseases has sensibly diminished; and M. Bacon, physician at Falaise, that in the hospital for children, formerly filled with scrofulous cases, no such disease is now to be found. Four ob servers sent various observations, five of which are very detailed, and have for their objects cases of rickets, not indeed cured, but modified in a remarkable manner, and the progress of which was either stopped, or sensibly retarded, by vacs cination. The power of walking recovered, strength increased, and the solidity of station re-established, were the most sensible effects that resulted; and in these cases the numerous punc tures along the spines were the means by which they flattered themselves with having obtained success. Three observers have spoken of the tinea capitis. One of the observations is de tailed, and gives an account of a tinea of a yel low colour, yielding a copious yellow humour, of the consistence of honey. Twelve punctures were made upon the head itself. When the vac cinal crusts fell off, the crusts of the tinea dried up, fell off, and the cure was complete. Five observers furnish numerous facts respecting vaccination performed on patients labouring under nervous disorders. Five of these are detailed. A megrim which continually tortured a young man of fourteen years of age, for several years, vanished after the suppuration of the cow-pox. Daily convulsions, during ten months, in a child of twenty months, which had not been alleviated by medicine, became less violent during the progress of vaccination, and afterwards disappeared altogether. Various convulsive diseases, three of which were epileptic, were suspended during the progress of the cow-pox. Afterwards they continued to recur, but at longer intervals. Thres of them, one of which was hereditary, ceased altogether. In one that had convulsions every

C

day, the vaccination was performed during sleep, because it would have brought on a fit if the patient had been awake. The epilepsy disappeared the ninth day after the vaccination. In him, who was afflicted with an hereditary epilepsy, and who was cured, vaccination was performed by incision, and the pustules were converted into an ulcer. Ten observers furnish va rious observations, four of which are detailed, and relate to periodical and obstinate fevers, such as quartans, double tertians, and quotidians. They were cured by vaccination. Two quotidians, with which young men of twentyeight were afflicted, had lasted for ten months; a double tertian, in a child of three years, had lasted three months. They ceased after vaccination. In four persons afflicted with intermittents, and vaccinated, the cow-pox appeared only upon one, and he alone was cured.

Several other observers, to the number of fourteen, have furnished various remarkable facts respecting different other diseases. In an infant, a year old, a palsy of the left arm, which had lasted two months, disappeared a month after vaccination, performed by making six punctures in the diseased arm. A great number of violent coughs have been suspended, moderated, or cured. The consequences of suppressed measles, namely, a dry cough, fever, and diarrhea, were cured by a cow-pox induced by twenty punc tures, during the suppuration of which a strong fever and miliary eruption occurred. A violent pain in the joint of the left thigh, with which a child of nine years of age was afflicted, with a threatening of spontaneous luxation of the limb, was treated by means of eighteen punctures round the diseased joint. Sixteen pox, the aureolas of which were confluent, occasioned fever, and then suppurated. Soon after the pain of the joint disappeared, and the cure was complete. A white swelling of the knee in a child of eight years of age, and a deafness which had increased for eighteen months in a child of six years of age, were both cured by vaccination.

Such are the facts which we have collected respecting the diseases existing at the time of vaccination, and cured by that process. We have noticed those only which are related with precision. We do not think that they ought to be always considered as cures due to vaccination. Separately taken, we do not see in them any thing else than a coincidence between the time of cure and vaccination; but taken collectively, we think that the number of facts, and the circumstances accompanying those which we have particularly noticed, give at least a presumption in favour of vaccination, more than suficient to Counterbalance the facts which have been alleged in favour of the small-pox, in what way soever that disease is communicated. We acknowledge, at the same time, that a comparison between vaccination and inoculation for the small-pox, in this point of view, cannot be fairly made, because a much greater number of cases of the former than of the latter have been given to the public. Vaccination, under the special protection of government, bas become the object of a regular and active correspondence, in which few facts have escaped observers, only in danger of being led astray by their zeal. Inoculation, on the other hand, but little favoured by government, was become the object of enterprises, in which a spirit of cupidity was much more prevalent than spirit of observation.

It will be asked, perhaps, whether, if we admit an equality of advantages in favour of vac cination and inoculation, considered as a remedy for different diseases, it would not be of advan tage to preserve the inoculation for the smallpox as a means of utility in certain situations.

We answer, that in such a comparison we ought not to leave out the dangers of a contagion, subtile and persevering like that of the small-pox, compared with the virus of the cowpox, which can only be communicated imme diately, because the least alteration destroys its properties. We ought also to reckon for some. thing the hope at present entertained of being able to destroy the small-pox altogether. Could houses for inoculation, though established under the care of the police, be subjected to laws SO severe, and to a sequestration so exact, as to prevent completely the spreading of the smallpox from them, something might be said in its favour; but whoever considers the nature of man, and the state of society, must be convinced of the impossibility of securing any such object. In our opinion, even admitting vaccination and inoculation to be equally efficacious in removing other diseases, the balance in favour of vaccination is so strong that it is impossible to hesitate one moment about preferring it.

VI-How far can we depend upon the preser vative efficacy of the cow-pox, compared with the same advantage resulting from the small-pox, natural or inoculated? What consequences follow from this, properly considered, in the one or the other virus?

Nobody disputes the power of the cow-pox to preserve from the small-pox: and this question, which at the commencement was the most important of all, has now become only secondary to various others that have been put, and most of which we think we have already answered. At the same time, to this question must be referred a variety of other particulars of considerable interest, such, for example, as the distinction between the true and false cow-pox, the eruptions that have been confounded with the small-pox, the changes introduced in the bills of mortality by the introduction of the cow-pox, the hopes of destroying the small-pox, or of driving it out of the civilized world.

The idea of the faculty of preserving from the small-pox divides itself into two questions. One may be thus stated: Will an individual, after being vaccinated, if he be placed in a situation proper to produce the small-pox, and which usually produces it, continue exempt from that disease? The solution of this question can only be obtained by a multitude of experiments; and that solution will give, then, not absolute certainty, but degrees of probability proportional to the number of experiments undertaken to resolve the question.

The other question is this: Is it impossible for a vaccinated person to be infected with the smallpox? Experience cannot decide, in the athrmative, the question when thus stated; but a single observation is sufficient to decide it in the negative. If that observation does not exist, the question must continue insoluble; because, in order to resolve it, we must be acquainted with the nature of the virus of small-pox and of cowpox, with all the circumstances which are capable of excluding or producing contagion, and with the peculiar dispositions which prevent men from

contracting it: all of them things absolutely unknown to us.

We must therefore confine ourselves to the first of these questions, and inquire into what confidence we may repose in the preservative power of the cow-pox. Such is the nature of the question to be resolved. We thought it necessary to fix its nature with precision, before proceeding to collect, as we have done with the other questions, the positive elements of its solution. Let us establish, in the first place, the nature of the facts which ought to constitute these elements.

It is obvious, in the first place, that we ought to exclude all those in which the characters of the cow-pox have not been ascertained. Some persons have considered the difference between the true and false cow-pox as a subtilty; but we answer, that when the characters, taken from the epoch of development of the form and appearance of the pock, of the nature of the humour contained in it, of the manner of its desiccation, and of the mark which remains after it has dropped off, are so distinct from each other, as in the true and false cow-pox: when to this difference is joined the determination of the circumstances upon which the failure of vaccination usually depends, as, for example, the too late period at which the virus has been taken, the changes in the cow-pock which have occasioned the mixture of pus with the true limpid liquor of the cow-pock-when these circumstances have been accurately observed, no farther ambiguity remains, and the distinction between the two kinds of pock is perfectly established, and may be easily determined.

This difference was established in consequence of errors committed in the first experiments. At Paris we were in possession of the false cow-pox matter, and were not acquainted with the effects of the true till Dr. Woodville made a journey to France, and naturalized among us the true matter. At Geneva false cow-pox matter imposed upon the physicians, and disappointed their hopes during twenty-one months, till, in May, 1800, the virus sent by Dr. Pearson succeeded completely.

The different characters of the true and false cow-pox matter have been already pointed out in the report inserted in the fifth volume of the Physical and Mathematical Memoirs of the Institute. They have been repeatedly published by the central committee of the society of Paris; they are described in several parts of the Bibliotheque Britannique, and in various other publications. Dr. Sacco has given at the end of his work very good plates, where both the true and the false cow-pock are represented.

Besides this, Dr. Sacco, endeavouring to fix the time when the cow-pox may be usefully communicated, has determined by experiment the relation between the probability of success, and the successive days in which the virus has been collected. According to his observations, supposing that the cow-pock begins to appear on the third day, as usually happens, the success may be considered as certain if the virus be taken between the fifth and eighth day, reckoning from the time of the puncture; or between the third and sixth day, reckoning from the appearance of the pock. He found that when the matter was taken on the sixth day from the appearance of the pock, out of 100 punctures, ninety-five succeeded; when on the seventh, ninety-two;

when on the eighth, eighty-eight; when onthe ninth, eighty-five; when on the tenth, eighty; when on the eleventh, fifty; and when on the twelfth, only from ten to fifteen. Besides this, the longer time elapses before the matter be extracted from a pock, the more likely is the pock to suppurate, and be converted into an ulcer. M. Sacco recommends, likewise, in order to be more certain of the efficacy of the matter, to avoid opening the pock too near the centre where the puncture was made, but to take the matter from as nearly as possible the outer edge of the pock, where it is more uniformly pure and limpid. Notwithstanding the various ingenious modes that have been contrived to transport the matter from one place to another, the most certain method of vaccinating, when it can be done, is to take the matter out of one arm, and immediately introduce it into another.

A second order of facts which ought to be excluded from the comparison, consists in observations of eruptive diseases, distinguished by the name of the small-pox, but which from their characters belonged evidently to the chicken-pox, or to some anomalous eruption, which have but a faint resemblance in form to the small-pox, but are in other respects quite different. Such eruptions show themselves every day upon children who have had the small-pox; and when they appear before that disease, they do not prevent it from infecting the patient. An attentive observer can easily distinguish such eruptions. The small-pox have a regular progress which cannot be mistaken; and when they are confluent they can be still confounded with other eruptions, which are usually exempt from all danger, and even from severe illness. Every observation then, which does not give as the essential characters by which the small-pox is distinguished from other eruptive diseases, and in which we do not find the fever of the commencement of the disease, the eruption, the suppuration, the fever of intumescence which accompanies it, and the desiccation-every such observation cannot come into comparison with the observations in favour of the present question.

There is a third order of facts which cannot be admitted into the comparison of which we speak; we mean those cases in which a true sinall-pox makes its appearance during the time of vaccination, at an epoch when we must suppose that the infection was caught before the cow-pox could exert its preventive powers. This point has been discussed in the first report to the Institute. We have already, in the memoir, given several examples of it, in speaking of the eruptions and diseases ascribed to the cow-pox. On this point Dr. Sacco has made some curious experiments, to determine the precise time when the small-pox may still appear after vaccination. Supposing the cow-pox to appear on the third day after the puncture, the inoculation for the small-pox performed between the first and fifth day occasions the appearance of the small-pox between the seventh and eleventh day. Inoculation performed on the sixth or seventh day occasioned a slight inflammation of the part punctured, without any general eruption. Either no pox appeared over the punctures, or if they did they speedily dried up. Inoculation performed from the eighth to the eleventh day produced a slight alteration at the place of the puncture, seldom a pock, or at least it very specdily dried up. Inoculation with small-pox matter

being performed on sixteen infants between the eleventh and thirteenth day after vaccination, three of them only exhibited a slight redness at the place of the puncture, while the thirteen others had no symptoms whatever. If the forma tion of the cow-pock be later than the third day, as happens sometimes, in that case the possibility of the small-pox infection will be extended to a time proportionally longer.

These details appeared to us necessary, in order to show to what degree of exactness observations on the preservative power of the cowpox have been carried, and to show that the distinctions to which these researches have given origin are far from being, as some persons wish us to believe, subtilties and subterfuges invented to excuse the want of success.

Now in applying the remarks that have been made to the alleged observations of small-pox appearing after vaccination, if we exclude all those which want the conditions necessary for rendering them creditable, we find very little which can come in competition with the facts on the other side. There are, however, some, against which it is difficult to start any plausible objection. The Jennerian Society of London evidently admit the existence of such, in articles nine, ten, eleven, fourteen, and fifteen, of their report. The College of Surgeons of London say, that out of 16,438 cases of vaccination there were fifty-six, that is, one in 3,000, where it was insufficient to act as a preservative from the small-pox. But they have not informed us what was the immediate effect of these vaccinations, and to what circumstances their insufficiency could be ascribed. The authors of the Bibliotheque Britannique have inserted in their work a letter from London, dated 5th August, 1811, stating that the national cow-pox establishment in London had published two cases of small-pox occurring after a most successful vaccination. "These cases," says the letter," are well ascertained, and admitted on the part of the establishment. But they publish, at the same time, three cases of natural small-pox occurring twice in the same individual, after an interval of eleven years."

The correspondence of the central committee of Paris contains some similar examples. Six observations were communicated by men well informed, and free from prejudice; but they were not accompanied with details sufficient to remove all uncertainty. Two of these announced small-pox appearing in the midst of an epidemic small-pox, which afflicted Beauvais in the autumn of 1810. But the children in whom this disease appeared had been vaccinated when the cow-pox was first introduced into France; and as no details are given, it is very possible that the disease communicated was the false cow-pox, at that time so common in this country. All the other children, vaccinated in the same place, and at later periods, continued exempt from the smallpox. There is a fact, which was verified by several members of the committee, and we our selves saw the infant covered with a very numerous, but favourable small-pox, on the 7th December, 1806 This child, called Emma Kerouenne, lived in the old street of the Temple, No. 93, and had been successfully vaccinated on the 24th March, 1804, by M. Lanne, physician in Rue Français, who had preserved an account of the vaccination, and its progress. It is therefore evident that it is not impossible for a child that

has been vaccinated to be afflicted with the smallpox. Nor indeed ought we to look for any such impossibility, as it has been well ascertained not to hold, even after inoculation, with the matter of small-pox.

But what degrees of probability do these observations leave, that vaccination will be a preservative from small-pox? We may obtain it by comparing the number of individuals who have taken the small-pox after vaccination with the whole number vaccinated, and who have not caught the infection, though repeatedly exposed to it. Another base of this evaluation is the number of counter experiments made, either by inoculation, or by placing persons that have been vaccinated in contact with those that are afflicted with the small-pox.

If we take the result of the correspondence of the central committee of Paris, the seven observations above-mentioned, supposing them all exact, are to be opposed to no fewer than 2,671,662 cases of vaccination. If it be objected that these seven observations, the only ones with which the committee were acquainted, are in all probability not the only ones which have occurred in the empire, we answer, that even these seven are not altogether free from uncertainty; and that the 2,671,662 vaccinations mentioned by the committee are far from being the whole number hitherto performed in France. These two numbers, being the whole obtained by the same means, are very fairly comparable with each other. They give us the ratio of 1 to 381,666.

With respect to counter-experiments, they are of three kinds; those made by inoculating with small-pox virus; those resulting from coming in contact with infected persons; those resulting from the reports of epidemic small pox in villages, from which very few persons escape. The accounts transmitted to the committee present 640 individuals put to the test of inoculation; 680 persons living with individuals afflicted with the small-pox, and in contact with them, yet escaping the disease, while every other person took it; and 4312 who in the midst of epidemics affecting whole villages escaped the general contagion: making in all 5552 individuals that remained free from the contagion, in circumstances either artificial or natural, in which they ought, had it not been for vaccination, to have been afflicted with the disease.

Similar results have been obtained in all other countries of Europe.

From all these facts, it is impossible not to conclude that the probability that vaccination will preserve from the small-pox is as strong as that inoculation with small-pox virus itself will prove efficacious; or that the small-pox will not recur a second time in the same individual: for it appears to us unreasonable, or at least premature, to conclude that small-pox will recur after the one oftener than the other.

If to these observations we join those which are their natural consequence, and which have been attested by physicians and magistrates, both in France and in other countries, that small-pox epidemics have been stopped in their progress by vaccination; that they have been excluded from those villages where vaccination had been generally practised; that these epidemics, which used to return at stated periods, have ceased to appear at their usual epochs; that several villages have ceased to know the small-pox, and that it bas