Among the various changes of incidence that have attended the recent decline of smallpox in England, Ireland and Scotland, there is one that calls for more extended notice, namely, the fact that the malady has in great part ceased to be an infection of infancy and childhood and has become more distinctively an infection of adolescence and mature age. In no period of its history has smallpox been so purely an infantile complaint as measles[1175], nor so purely a malady of childhood and early youth as scarlatina or diphtheria[1176]. When it first rose to prominence in England, from the reign of James I. onwards, it attacked adults in a large proportion; of which fact the evidence, although not statistical, is sufficient. But, as the disease became nearly universal and ubiquitous, it was so commonly passed in infancy or childhood, that few grew to maturity without having had it. The number of adult cases diminished in proportion as the disease became more nearly universal. In the great period of smallpox in the 18th century, about nine-tenths of the deaths occurred under the age of five, and nearly all the remaining fraction between five and ten years, at Manchester, Chester, Warrington, Carlisle and Kilmarnock. But in London there were always a good many adult deaths, the reason commonly given being that there was a steady influx to the capital of domestic servants and others from country parishes where the epidemics came at sufficiently long intervals to let many children grow up without incurring the risk of it. Also at Geneva and the Hague, in the 18th century, there were many more deaths above the age of five than in the English provincial towns at the same time.
Ages at Death from Smallpox at Geneva (including Measles) and at the Hague (Duvillard).
| All ages | 0-1 | -2 | -3 | -4 | -5 | -6 | -7 | -8 | -9 | -10 | -15 | -20 | -25 | -30 | -35 | -40 | -45 | |||||||||||||||||||
| Geneva (1700-83) | 3328 | 555 | 608 | 588 | 426 | 346 | 232 | 185 | 99 | 67 | 44 | 84 | 36 | 26 | 21 | 0 | 0 | 0 | ||||||||||||||||||
| The Hague (15 years of 18th cent.) | 1455 | 172 | 170 | 179 | 224 | 160 | 148 | 114 | 78 | 58 | 23 | 47 | 17 | 24 | 14 | 10 | 8 | 3 |
Twenty-four per cent. of the smallpox deaths in the 18th century at Geneva were above the age of five years, and at the Hague thirty-seven per cent., while in the former the ratio would probably have been higher but for the inclusion of measles. But, with this comparatively high ratio of deaths above the age of five, smallpox was a much less important cause of mortality at Geneva and the Hague than at Manchester, Glasgow, Chester, and most other provincial cities of this country, making about a fifteenth part of the deaths from all causes in the former, and as high as a sixth part in the latter.
The infantile character of smallpox was as marked as ever in the epidemic of 1817-19; of which the Norwich statistics are sufficient proof. As late as the epidemic of 1837-40, smallpox was still distinctively a malady of infants and young children in Britain, although that was by no means the case on the continent of Europe at the same time. The following was the age-incidence of fatal smallpox at Liverpool and Bath in the last six months of 1837.
| At all ages | Under 1 | 1-2 | 2-3 | 3-4 | 4-5 | 5-6 | 6-10 | Above 10 | |||||||||||
| Liverpool | Deaths | 495 | 143 | 127 | 77 | 64 | 24 | 19 | 20 | 25 | |||||||||
| Ratios per cent. | 100 | 28·65 | 25·45 | 15·43 | 17·63 | 7·81 | 5·01 | ||||||||||||
| Bath | Deaths | 151 | 33 | 31 | 33 | 17 | 17 | 6 | 6 | 10 | |||||||||
| Ratios per cent. | 100 | 21·56 | 20·26 | 21·56 | 22·2 | 7·84 | 6·53 | ||||||||||||
In the third year of the epidemic, 1839, the ratio of deaths above the age of five was still less at Manchester, Liverpool and Birmingham, being only four and a half per cent. (26 in a total of 522). At Glasgow, from 1835 to 1839, twelve per cent. of the smallpox deaths were above the age of five (see p. 600). These are the rates of provincial cities; but in a total of 8714 deaths in the year 1839, added together from London and the provinces, about twenty-five per cent. were over five, and of these a moiety were over ten years:
| All ages | Under five | Five to ten | Above ten | |||
| 8714 | 6453 | 1122 | 1139 |
A good deal of that mortality above the age of five must have come from London, according to the probability of the following table, which is of six years’ later date, but the nearest that can be got for London alone:
London, 1845. Ages at Death from Smallpox, Measles and Scarlatina.