III. That the death-rate in recorded cases of post-vaccinal smallpox has progressively increased in all cases, with and without marks, from 1.75 per cent. in 1819-35, to over 10 per cent. in 1870-79, and in cases with marks from 6.9 per cent. in 1831-51 to 9.2 per cent. in 1870-79.

IV. That this increase in mortality has been remarkable in the best vaccinated classes of cases, the death-rate in cases with three or more cicatrices in 1870-79 being twice what it was in 1852-67 ; and the death-rate in cases with three or more good cicatrices in 1870-79 being thrice what it was in 1852–67.

V.-That the proportion in which vaccinated children are attacked and cut off by small-pox has alarmingly increased, being many times greater during the last decade than it was thirty or forty years earlier; and

VI. That while the death rate in small-pox occurring in unvaccinated persons has risen in the different groups recorded, and was exceptionally high in 1870-1879, the progressive advance of mortality in post-vaccinal small-pox is not to be attributable to epidemic influence, being equally observed in successive groups of cases in which the mortality from natural small-pox shows a diminution.

Every one of the counts in this indictment may be admitted; they are paralleled elsewhere in these pages in all essential features. But that these results are due to the use of long-humanized virus, per se, is not substantiated. If humanized virus remained unimpaired by its successive transmissions during the first twenty-five years of its use-and this is conceded even by the most interested of the advocates of bovine virus-there must be some reason for its subsequent impairment without assuming a change in character caused by its normal transmission through other human systems after Jenner's death. Jenner, himself, pointed out this reason. Everywhere throughout his writings he lays stress upon the proper performance of the operation; upon the importance of a perfect development of the vaccine vesicle, and of the undisturbed and normal progress of every stage of the vaccinal phenomena. Short of this he pronounced no vaccination to be fully protective. Still less did he countenance the use of lymph from such a non-protective vaccination, with the vain hope of securing full protection of others by it. He went further than do the advocates of the deterioration theory. They only assume that vaccine virus gradually loses its power of protecting against small-pox by successive transmissions through the human system. He asserted, after twenty years of characteristic painstaking investigation and record of facts, that the virus may undergo a change that will render it unfit for further use by passing even from one individual to another; and he pointed out the causes which might produce such change, and the indications by which such change might be recognized. Vaccine lymph from a perfect eighth-day vesicle-produced upon the arm of a healthy subject by lymph transmitted from arm to arm continuously since the original operation by Jenner himself-will to-day produce, in another healthy subject, the same vaccinal phenomena, identical in every respect of time, of appearance, duration and disappearance, and resulting cicatrix, as those produced in 1798 by Edward Jenner in England, or

in 1800, by Benjamin Waterhouse in the United States; and will confer as great a degree of protection, in this eighty-sixth year of vaccination, as did the original operations.

Increasing frequency of small-pox, within the last thirty years among vaccinated persons, and the greater death-rate of post-vaccinal small-pox in the same period, are not to be ascribed to any loss of protective power in humanized virus; but rather to the causes elsewhere pointed out-to ignorance and want of care in the performance of the vaccinal operation; to absence of intelligent supervision over the progress of the vaccinal phenomena; to the use of virus from defective or non-protective vaccinations; and to the neglect of revaccination at the proper intervals.

To sum up, briefly, the foregoing considerations, on the choice of virus: Bovine virus has to recommend it—(1), convenience and certainty of supply; (2), popular favor on account of its freedom from danger of transmitting other diseases peculiar to mankind. Humanized virus has-(1) promptness and uniformity of action; (2), mild, local and constitutional symptoms; (3) facility of propagation by every physician for himself, whereby he may be assured of the character of the material he is using.

PRACTICAL CONCLUSIONS AND PROPOSITIONS.

IN the foregoing pages-The Small-Pox Epidemic of 1880-82; Vaccination in Illinois; and The Relations of Small-Pox and Vaccination -it is believed that the foundation has been laid for the following propositions and conclusions, based upon practical experience and supported by the concurrent testimony of a large number of competent observers. These are offered as an epitome of the subject, for the consideration of legislators; of municipal, sanitary and other authorities; of individual members of the community-parents, guardians, employers and others; and of the medical professioneach and every one of which classes owes a duty to the public welfare in this connection.

It has been demonstrated

I. That Small-Pox has increased in frequency of outbreak in Illinois, and in the extent of territory invaded in each successive outbreak, during the past thirty years; and that such outbreaks are costly in human life and suffering, as well as from a merely material standpoint.

II,-That such increased frequency has kept pace with (a) the natural growth of population; (b) the increase of population by immigrants; and (c) the multiplication of means and facilities of communication. By the first and second of these factors, (a) and (b), the number of unprotected individuals, i. e., those susceptible to the small-pox contagion, accumulates from time to time up to the point when the introduction of the contagion from without is sufficient to cause an epidemic outbreak. By the second and third of these factors, (b) and (c), the contagion is introduced and disseminated, whenever the disease becomes prevalent in countries or places with which this country has commercial relations, and especially when, during such prevalence, foreign immigration rises above the average.

III. That not only may such epidemic outbreaks be prevented with absolute certainty by Vaccination, universally and properly performed; but the disease itself might be entirely eradicated, and its reproduction be rendered practically impossible if every individual were efficiently vaccinated in infancy, and the operation repeated at proper intervals of time.

IV. That in order to secure the universal performance of vaccination in this country-whereby epidemic outbreaks, at least, may be positively prevented-it is necessary to supplement whatever measures of compulsory enforcement may be deemed advisable, by the education of the people to a correct estimate of the value of the operation, and of its freedom from evil results, when intelligently and properly performed; such education entailing upon the medical profession and upon sanitary authorities the imperative duty of securing its proper and intelligent performance.

V.-That compulsory vaccination of all public scholars before admission to the school-room, as well as of their teachers, is justifiable if on no other ground than that it is the duty of the State, which in other ways directs and superintends the matter of public instruction, to guard against the interruption of schools by the prevalence of small-pox; and in like manner it is the right of the State to demand such precautions on the part of inmates, employés and officers of State institutions as will secure them against the invasion of this disease. So, too, the State may demand that common carriers and others especially exposed to the contagion and to the risk of conveying it from place to place, shall protect themselves against such exposure and risk.

VI. That vaccination, compulsorily secured to the extent indicated. in the previous proposition, in addition to that voluntarily procured by the large majority of intelligent persons, might be made so popular and its value so apparent, by its proper performance, as to largely obviate the necessity for any other measures of legal enforcement in order to secure its substantially universal performance in all enlightened communities.

VII. That since few communities are yet so enlightened as not to embrace a certain proportion of negligent, prejudiced or ignorant individuals, compulsory vaccination-enforced by legal provision and supervised by competent sanitary authority-is necessary to the present protection of communities from epidemic outbreaks of smallpox, and to the. ultimate extinction of its contagion. Neither of these desirable results can be attained with a disease so exceptionally contagious as this, so long as even a few individuals remain unvaccinated, to become propagators, conveyors and diffusers of the poison. The extreme right of any individual to risk his own health or life would be tenable only so far as the exercise of such right could be demonstrated not to involve risk or injury to others. Such demonstration is practically impossible in the case of small-pox; and it is both the right and the duty of the State and local authorities to enforce the employment of a measure of protection which, when efficiently and properly performed, has been shown to be adequate against the scourge of small-pox-as was abundantly proven, during the recent epidemic, by the results of the action, in this direction, of the STATE BOARD OF HEALTH and of local authorities.

VIII. That the proper performance of vaccination demands in greater degree than is usually bestowed: Care in the selection of virus; painstaking in the details of the operation; intelligent, experienced supervision over the progress of the vaccinal disease; and inquisition into the sufficiency of the vaccinal protection, by revaccination from time to time.

IX. That the charges of failure of vaccination as a protection against small-pox-and so much of the hostility to this measure as is not due to ignorance or unreasoning prejudice-have grown out of a culpable neglect of the essentials of vaccination, for which the medical profession and medical teachers are, primarily, and still very largely, responsible. Wherever vaccination is now as skilfully and intelligently performed and supervised as it was by Jenner and his immediate co-workers, it secures as great a degree of protection, with as few drawbacks and objections, as did their operations. is, therefore, the duty of medical preceptors and teachers to give the proper amount of practical instruction concerning vaccination to their students; and of individual practitioners to invest the operation with the importance and dignity to which the transcendent value of its results entitles it.

X.-That the alleged deterioration of humanized virus, and consequent loss of protective power, may be true only to this extent, to-wit, that every successive transmission of the virus through the human system increases the chance that want of necessary care and attention may result in the use of virus which is not the product of a typical vaccination, and which may thence be wanting in the normal degree of protective power. It is incumbent, therefore, upon every vaccinator to fully assure himself of the quality of his virus; and to this end there is no more certain way than by propagating and preserving it for himself. Should there, at any time, arise a doubt as to the character of the supply, it must be promptly discarded, and a new source established by recourse to bovine virus, scrupulously selected from a reputable and responsible propagator. A few removes of this from its original bovine source will readily modify its severity; and for many reasons such virus, humanized to this extent, is practically preferable to any other.

XI. That the relative advantages of bovine and of humanized virus are still sub judice as to the most important point, namely, their comparative protective powers. Humanized virus has been tested for more than eighty years; bovine for about sixteen. The former, descended in an unbroken line of vaccinations from the original operations of Jenner, still produces the same typical results, the same regular sequence of phenomena, as those obtained by Jenner himself; the latter produces almost as many varying results as there are propagators. The product of some of these is uniformly excellent, and its protective power, doubtless, as perfect as that of the true Jennerian lymph. In cases of emergency, however, where promptness of action is important, the preference must be given to the humanized. As to freedom from communicating other disease, it is abundantly proven that it is a physical impossibility for pure vaccine matter, either bovine or humanized, to produce any other

disease than true vaccinia; that the vaccinal disease is as truly sui generis as is small-pox itself, and cannot be converted into, or produce, any other constitutional disease.

XII. That, since small-pox occasionally occurs more than once in the same individual-thus proving that the susceptibility may be renewed-revaccination is the absolutely essential complement of primary vaccination; and should not alone be performed in all cases at or about the period of puberty, but should be repeated on all occasions of exposure, as well as during the epidemic prevalence of small-pox in any case where the sufficiency of the vaccinal protection may be the subject of doubt. And, finally,

XIII. That while, on the one hand, with the exception of an infinitesimally small number of insusceptible individuals, every unvaccinated person would contract small-pox in the course of a natural life-time, if exposed to the contagion, and fully one-half of those attacked would die, while of the survivors a large number would be hideously disfigured, maimed and disabled; on the other hand, if efficiently vaccinated and revaccinated, an equally infinitesimal number of hyper-susceptible individuals would contract the disease on exposure, and of this small number less than one in a hundred would die. La Condamine states that one-tenth of the human race, on the average, died annually of small-pox for centuries before the discovery of vaccination; during which period, in the language of Macaulay, the disease was always present, filling the church-yards with corpses, leaving on those whose lives it spared the hideous traces of its power, turning the babe into a changeling at which the mother shuddered, and making the eyes and cheeks of the betrothed maiden objects of horror to her lover. For this devastating and constant pestilence, Jenner substituted a mild affection of only a few days' duration; never causing death, suffering or disfigurement, when properly and intelligently produced; and conferring an immunity from the graver disease proportionate to its thoroughness and efficiency. To neglect or oppose its universal introduction is to carelessly, ignorantly or criminally invite avoidable suffering, disaster and death.

It would seem as though facts so incontestably proven as these, would only need to be properly brought to the attention of the public-and especially of parents and those having charge of the young-in order to secure the universal and proper performance of Vaccination.