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.
| Year. | From Smallpox. | Measles. | Whooping Cough. | Children under Two. | Children under Ten. | Total, all Ages. | |
| 1803 | 194 | 45 | 60 | 610 | 940 | 1860 | |
| 1804 | 213 | 27 | 52 | 583 | 863 | 1670 | |
| 1805 | 56 | 90 | 129 | 616 | 884 | 1671 | |
| 1806 | 28 | 56 | 162 | 517 | 786 | 1620 | |
| 1807 | 97 | 16 | 85 | 595 | 899 | 1806 | |
| 1808 | 51 | 787 | 92 | 1079 | 1775 | 2623 | |
| 1809 | 159 | 44 | 259 | 782 | 1187 | 2124 | |
| 1810 | 28 | 19 | 147 | 765 | 1027 | 2111 | |
| 1811 | 109 | 267 | 62 | 769 | 1274 | 2342 | |
| 1812 | 78 | 304 | 103 | 804 | 1278 | 2348 | |
| —— | —— | —— | —— | ——— | ——— | ||
| Total, | 1013 | 1655 | 1151 | 7120 | 10,913 | 20,175 |
To make the facts clear let us bring the results of the three decades together—
| Decade. | From Smallpox. | Measles. | Whooping Cough. | Children under Two. | Children under Ten. | Total, all Ages. | |
| 1783-1792 | 3466 | 211 | 854 | 7293 | 9,919 | 17,607 | |
| 1793-1802 | 2894 | 398 | 914 | 6277 | 9,050 | 16,685 | |
| 1803-1812 | 1013 | 1655 | 1151 | 7120 | 10,913 | 20,175 |