I began to reflect how different the case must be now; and to calculate the great saving of human life that must have arisen from the Vaccine Inoculation. At this time [1813] above 15,000 had been inoculated publicly at the Faculty Hall, and perhaps twice or thrice that number in private practice. In eight years [1805-12] little more than 600 had died in Glasgow of Smallpox; whereas in 1784 the deaths by that disease alone amounted to 425, and in 1791 to 607; which, on both occasions, exceeded the fourth of the whole deaths in the city for the year.

It seemed reasonable to infer that since the mortality from smallpox had so largely declined, fewer children must have died; but to Watt's astonishment the facts did not answer to the logic. He writes

To ascertain the real amount of this saving of infantile life, I turned up one of the later years, and by accident that of 1808, when to my utter astonishment, I found that still a half, or more than a half, perished before the tenth year of their age! I could hardly believe the testimony of my senses, and therefore began to turn up other years, when I found that in all of them the proportion was less than in 1808; but still on taking an average of several years, it amounted to nearly the same thing as at any former period during the last thirty years. This was a discovery I by no means expected, and how it could have come to pass appeared to me inexplicable.

We shall better understand Watt's perplexity over smallpox reduced and death unaffected, if we set before us the table of mortality for the decade during which vaccination was brought into practice in Glasgow.

DEATHS IN GLASGOW FOR TEN YEARS, 1803-1812.

To make the facts clear let us bring the results of the three decades together

Before making any commentary on these remarkable figures, it may be well to attend to what Watt had to say concerning them. He was satisfied that vaccination arrested smallpox, but it was plain that it did not arrest death, and he felt bound to find some explanation

From every circumstance that has come under my observation, the efficacy of Vaccine Inoculation appeared certain. The experience of pretty extensive practice had confirmed me fully in this opinion. But still the question recurred, how are we to account for the same, or nearly the same, number of deaths under ten years of age? As no new disease has appeared, the deficiency occasioned by the want of Smallpox must have been made up by a greater mortality among the other diseases of children. Has it been equally divided among them, or has a greater share fallen to some than to others? To solve this question is the chief object of my inquiry.

To ascertain the fact, he divided the thirty years, 1783-1812, into five periods of six years each, and thus set forth the average proportionate mortalities

The first three of these periods, 1783-1800, had passed before the Vaccine Inoculation could have had any influence [observes Watt]; in the fourth, 1801-1806, it had nearly reached its maximum; and in the last, 1807-1812, it may be said to have been pretty fully established, perhaps as much so as in any other city in the empire.

Vaccination having been introduced to Glasgow to save life, Where was the salvation? Smallpox had fallen.

off, but if its victims were merely assigned to other modes of death, where was the advantage? Watt continues—

The first thing which strikes the mind on surveying the preceding Table, is the vast diminution in the proportion of deaths by the Smallpox-a reduction from 19.55 to 3.90 per cent.; but the increase in the Measles column is still more remarkable-an increase from 93 to 10.76 per cent. In Smallpox we have the deaths reduced to nearly a fifth of what they were twenty-five years ago, whilst in the same period, the deaths by Measles have increased more than eleven times. This is a fact so striking, that I am astonished it has not attracted the notice of older practitioners.

The greatest number of deaths from Smallpox in any one month during the last thirty years was 114 in October, 1791. In the following December they were 113. These are the only two instances in thirty years when the deaths by Smallpox amounted to 100 in a month. But these were slight visitations when compared with the ravages which have been committed in an equally short time by Measles. In May, 1803, the deaths by Measles alone amounted to 259, in June to 260, and in July to 118. In December, 1811, they amounted to 161, and in the January following to 130. What an amazing difference when we compare these numbers with 433, the sum of all the deaths by Measles in eighteen years preceding 1801! In the last five years 1430 have died of Measles in Glasgow.

This prodigious increase in the mortality from Measles was naturally referred by some observers to the practice of Vaccination, and Watt held there was ground for the assumption inasmuch as when Smallpox preceded Measles it made Measles milder

When Measles was so prevalent and fatal in 1808, I was often told that it was owing to the Vaccine Inoculation; but this I considered an idle tale, the invention of those who were hostile to Cowpox. I could readily admit that more must die of Measles than formerly; for some of the weak and unhealthy, who would have died of Smallpox (saved from Smallpox) would fall a sacrifice to Measles; but I could not then go farther.

But however novel and strange the opinion may appear, it must be admitted that while Smallpox was in full force, it had the power of modifying and rendering Measles mild; and now that Smallpox is in great measure expelled, Measles is gradually coming to occupy the same ground. I am sorry to make this statement, but the facts, at least with regard to Glasgow, are too strong to admit of doubt.

That Measles should have been modified by Smallpox is rendered

highly probable by the manner in which the Vaccine Disease prevents Smallpox or renders it so mild as to be without the smallest danger. May not Smallpox have a similar effect in relation to Measles?

When Smallpox was in full force, few children escaped, and most of those who had Smallpox and Measles had Smallpox first. This, I believe, will have been the case with more than nine-tenths of the community. Still, however, as Measles came round, it occasionally had precedence of Smallpox, and it was perhaps chiefly among such patients that it proved fatal. In looking over the registers of former years, I find the deaths by Measles were generally among very young children.

He was even disposed to believe that Smallpox, on the whole, exercised a beneficial influence in the eradication of latent disease

An opinion has prevailed with some, that Vaccination does positive harm by infusing peccant or vicious humour into the constitution. I do not see the smallest ground for this hypothesis; but that Smallpox does good to those who survive the disease by rendering the system insusceptible of other infections, or by rendering them milder when incurred, must, I think, be admitted. I do not presume that the constitution is improved by Smallpox, but perhaps by eradicating certain unobserved deviations from health, which, if not early removed by the accession of some acute disease, would have proved the seeds of early mortality by gaining a deeper hold of the constitution before Measles and other epidemics of later appearance came round.

In this point of view, we are not to consider Smallpox as peculiarly fatal, but fatal merely as having the start of some other diseases. Measles, Chincough, Croup, and Scarlet Fever would have proved equally fatal had any of them occurred first.

It is only on this principle that we can explain how it happened that thirty years ago not one in a hundred died of Measles, whereas now one in ten dies. Thirty years ago as few escaped Measles as now, but before they were affected they had generally passed through Smallpox, by which the secondary disease was so modified as to be almost completely divested of danger.

Watt, it will be observed, treats smallpox throughout as a malady of childhood; thus confirming Monro's observation in 1765, that "the inhabitants of Scotland generally have smallpox in their infancy or childhood, very few adults being seen in the disease."

From the preceding excerpts, it is not difficult to comprehend Watt's position. He was persuaded of the

prophylaxy of vaccination; he was satisfied that it had reduced smallpox in Glasgow; but, to his astonishment, he discovered that it had not reduced the general deathrate; and that in so far as smallpox had been displaced, other ailments, and specially measles, had maintained the tale of fatality.

The discovery that the fall in smallpox was compensated for by a rise in deaths from other diseases was a remarkable discovery, the importance of which is as yet far from appreciated. Watt was however at fault in attributing the decline of smallpox in Glasgow to vaccination; and in failing to inquire whether the phenomenon had any relation to vaccination whatever. He is the best scientific demonstrater who most completely exhausts the possibilities to the contrary of what he seeks to establish. Supposing vaccination to be as powerful against smallpox as its promoters averred, the causes in Glasgow was not commensurate with the effect. Nowhere was vaccination more practised. 15,000 were vaccinated at the Faculty Hall, says Watt, "and perhaps twice or thrice that number in private practice"-a loose and questionable statement. The 15,000 operated on at the Faculty Hall in the course of ten years were the poor, the vast majority in Glasgow and elsewhere, and the chief sufferers from smallpox. The assumed "twice or thrice that number" were those who employed their own medical men a luxury less common then than now. The population of Glasgow approached 100,000, and it is obvious that the larger part must have lived outside the fortification of the Jennerian rite.

But admitting that all, or nearly all, in Glasgow were vaccinated who had not had smallpox, still that would afford no proof for what was claimed. Watt was cautious, and held closely by his Glasgow evidence, content to have it taken for what it was worth; but had he ranged wider, he would have discovered that the fall in smallpox extended over Europe, and was as well marked in Vienna as in Glasgow, in Stockholm as in London, in Italy as in Denmark. As in Glasgow the