At the end of an epidemic at Leeds, in 1781, which had attacked 462 and killed 130 during six months, “in the next six months there were inoculated 385, of whom four died” (two by contagious smallpox). A second general inoculation was carried out in Leeds sometime previous to 1788. Lucas, writing in that year, says: “The result of two general inoculations in Leeds has been that the smallpox has since been less frequent and less fatal[962].” This will be a convenient opportunity of considering the gross effects of inoculation upon the prevalence of smallpox.
The first and most obvious consideration is that it usually came too late. “Most born in London,” said Lettsom quite correctly, “have smallpox before they are seven”—i.e. before the age for admission to the inoculation hospital. He might have added that, if they had run the gauntlet of smallpox in London until they were seven, they were little likely to take it at all. The inoculations in London were therefore done upon a very select class (they were, in fact, a very small number), who may be assumed to have escaped the perils of smallpox in London in their childhood, or to have come to London (as many did) from country places where smallpox broke out as an epidemic only at long intervals. In other large towns as well as the capital the inoculated must have been a residual class. At Leeds, with a population of 17,117, “the number of those who were still uninfected was found on a survey to be 700” at the end of an epidemic, of whom 385 were inoculated. If a general inoculation had been tried at Chester after the epidemic of 1774, there would have been only 1060, in a population of 14,713, to try it on. How many of these, above the age of childhood, were constitutionally proof against smallpox? The case of Ware, in Hertfordshire, after the epidemic in the summer of 1777, is so related by Lettsom as to bring out the ambiguity of much that was claimed for inoculation. “After about eighty had been carried off by it, a general inoculation was proposed, to prevent those who had not yet been attacked, and whose number was still considerable, from sharing the same fate. The alarm which had been excited induced most of the survivors to adopt this proposition, after which not one died, and the infection was wholly eradicated.” Eighty deaths in one epidemic is a large mortality for such a place as Ware in any circumstances; the smallpox for once had done its worst. But, says Lettsom, there were a few families of those hitherto untouched by the epidemic who did not submit to inoculation. Not one of them caught the disease—from their inoculated neighbours (Lettsom is arguing that there was no danger in that way), nor, of course, from the epidemic contagion. It cannot but appear strange to us that the natural cessation or exhaustion of an epidemic should not have been thought of. Dr Currie, of Liverpool, records that in the first general inoculation there in 1781 there were 417 inoculated gratuitously and about 100 more in private practice, and that “about three or four thousand liable to the disease were scattered in the same manner [as the inoculated], not one of whom caught the infection.” For a few weeks there was not a case of smallpox known in Liverpool, so that no matter could be got for inoculation. He adds, in the most ingenuous manner: “An important particular has been recalled to my mind by Mr Park; that previous to this first general inoculation, which extinguished the smallpox in so extraordinary a way, the disease raged in town with much violence and was very fatal[963].”
The general inoculations were often carried out in so haphazard a manner as to make them valueless for a scientific as well as for a practical purpose. A Bath surgeon of long experience wrote in 1800: “Whenever the inoculating rage once takes place whole parishes are doomed, without the least attention to age, sex, or temperament—no previous preparation, no after treatment or concern.... Are not scores and hundreds seized upon at once, for the incisions, scratchings, puncturings and threadings, without even a possibility of their being properly attended to? and whether they may or may not receive the infection is just as little known or cared about[964].” It must have been equally little known or cared about whether they had had smallpox in the natural way before. What Dimsdale found to obtain at St Petersburg would have been the rule elsewhere: “The general method was to search for marks, and, if none were found, it was concluded the party had not had the disease[965].”
Thus in any attempt to estimate the gross advantages of inoculation in the 18th century we are met on every hand by sources of fallacy. Whatever its theoretical correctness, it does not follow that the inoculation of smallpox was a practical success to the extent of its trial; and even its theoretical correctness will be thought by some, and was so thought at the time, to have gone by the board when the artificial disease was brought down to a pustule at the point of puncture, with or without a few bastard pocks on the skin near. I have found two instances in the 18th century history in which there are data for a rough practical judgment, although not for a precise statistical one. The first is the town of Blandford, in Dorset; the other is the Foundling Hospital in London.
During the smallpox year 1766, smallpox of a very malignant type broke out at Blandford in the first week of April[966]. It was estimated that 700 persons in the town (population 2110 in 1773) had not had the natural smallpox, and a general inoculation was resolved upon on the 13th April. “A perfect rage for inoculation,” says Dr Pulteney[967], “seized the whole town,” and in the week following the 16th April some 300 were inoculated, the total rising to 384 before the panic ceased; of these, 150 were paid for by the parish. There were thirteen deaths among the inoculated, but most of these confluent or haemorrhagic cases, seem to have been due to the epidemic contagious smallpox, which had been peculiarly fatal, with haemorrhagic symptoms, to the few that were seized before the inoculation began, and continued to be fatal to many. The mortality from smallpox for the year in the parish register was 44, and from all causes 104, or more than twice the normal[967]. The last epidemic of smallpox in Blandford had been in 1753, when 40 died of it, the deaths from all causes being 96. In that year also there had been a general inoculation to the number of 309. The parish register gives the deaths in an earlier epidemic, in 1741, which was a year of great distress and typhus fever all over England: 76 deaths are ascribed to smallpox (102 to all causes), which is a larger total from smallpox than in either of the subsequent occasions when general inoculations were tried. Comparing these three epidemics in a Table, with the associated circumstances, we get the following:
Statistics of Blandford in three Smallpox Years (Population in 1773, 2110).
| Year of Epidemic | Deaths from all causes | Deaths from Smallpox | Inoculations | Annual Averages of eight previous years | ||
| Marriages | Births | Deaths | ||||
| 1741 | 102 | 76 | — | 24·87 | 63·37 | 49·25 |
| 1753 | 96 | 40 | 309 | 19·37 | 50·62 | 49·62 |
| 1766 | 104 | 44 | 384 | 20·62 | 54·12 | 49·12 |
It will be seen that the higher mortality from smallpox in 1741 was associated with other things besides the absence of inoculation. The annual average of deaths for eight years preceding each of the three epidemics is almost the same. But the marriages and births for eight years preceding 1741 were much in excess of those in the periods preceding the other two epidemic years. In the former there was a much larger susceptible population of children, upon which the smallpox mainly fell; and that alone would account for more deaths from smallpox in the epidemic of 1741. But the year 1741 was peculiar in another way; it was the worst year of typhus fever and general distress in the whole of the 18th century, and in the circumstances the deaths from smallpox would have been unusually numerous for the cases. Another epidemic of smallpox without inoculation, in 1731, showed how mild smallpox could be. At a time when sixty families had the disease among them, a fire broke out on 4 June, and burned down the town. It is said that 150 ill of smallpox were removed to gardens, hedgerows and the arches of bridges, and that only one of the whole number died[968]. This is usually cited to show the benefits of fresh air; but if it be true, it shows more than that.
The Foundling Hospital may seem to offer all the conditions for a fair trial of the question. It had been a standing rule of the Governors, since the opening of the charity in 1749, that all children received into it should be inoculated. Sir William Watson, who states the fact, adds that he himself was “in a situation of superintending every year the inoculation of some hundreds.” Still, the rule may not have been uniformly carried out; and even in this community of children, it was not always possible to learn on their admission whether they had had smallpox before in the natural way[969].
The lists of the inoculated are longer in the later periods than in the earlier: thus, from March, 1759 to May, 1766, the annual average is something under a hundred, the inmates having been 312 in 1763; but from May, 1766 to July, 1769, the annual average is some two hundred and fifty, the inmates in 1768 having been 438. Sir William Watson, in his essay upon the inoculations at the Foundling, breathes no hint that such a thing as natural smallpox ever happened there[970]; but in another context he does casually mention that there was an epidemic of sixty cases, with four deaths, in the end of 1762, and another epidemic in the following summer, of “many” cases, nineteen of which, with eleven fatalities, occurred in children who had lately been through the measles and were weakened in consequence[971]. Another epidemic, as I find by the apothecary’s book of weekly admissions to the infirmary, happened in the winter of 1765-66, twenty-six names being entered as admitted for “natural smallpox.” After that date all the great epidemics appear to have been of measles, whooping-cough, influenza or scarlatina; but almost every year smaller groups of “natural smallpox” occur, of which the following have been collected from the available records: