Nettleton began his inoculations in and around Halifax during a considerable epidemic of smallpox in the winter of 1721-22, of which the following figures were collected by himself (as well as statistics for Leeds, Bradford, Rochdale and other places):
| Cases | Deaths | |||
| Halifax | 276 | 43 | ||
| Part of Halifax parish towards Bradford | 297 | 59 | ||
| Another part of Halifax parish | 268 | 28 |
In the town of Halifax the smallpox was of a more favourable type than usual, whereas in Leeds at the same time (792 cases and 189 deaths) it was more than usually mortal. In the country round Halifax there was more smallpox than in the town; but the epidemic in general ceased in the spring of 1722. As the people mostly disliked the idea of inoculation, Nettleton did not urge it upon them, but inoculated only the children of those who favoured it. Down to the 22nd of April, 1722, he had inoculated about forty, with one death; at the date of 16 June, he had done fifteen more, his total to the end of 1722 being 61. In 1723 he did nineteen inoculations, in 1724 none, in 1725 and 1726 about forty (in an epidemic of 230 cases, and 28 deaths in Barstand Ripponden and another part of Halifax parish), and in writing to Hartley of Bury St Edmunds in 1730, he gave his total at that date as 119, from which it appears that he had ceased to inoculate after 1726. His name does not appear again in the controversy, and it is probable that he acquiesced in the tacit verdict against inoculation which Jurin himself, in 1728, seemed to think was imminent.
Besides this centre of inoculation in Yorkshire in the midst of epidemic smallpox, the only other of importance in the first trials of the practice was at Boston, New England. The smallpox epidemic there in 1721 was a very severe one. There had been no smallpox in Boston since 1702, so that a large part of the population were susceptible of it. The infection was brought by a ship from Barbados in the middle of April, 1721, and made slow progress at first, according to the following table of deaths from it[911]:
Deaths from Smallpox in Boston.
1721-1722
| May | 1 | |
| June | 8 | |
| July | 20 | |
| August | 26 | |
| September | 101 | |
| October | 402 | |
| November | 249 | |
| December | 31 | |
| January | 6 | |
| Total | 844 |
In the course of the epidemic some 5989 persons were attacked, or more than half the population (10,565). All the rest, save about 750, had been through the smallpox before. Inoculation played a very subordinate part amidst these dreadful scenes of smallpox. Its instigator was the Rev. Dr Cotton Mather, who had been shown by Dr Douglass the numbers of the Philosophical Transactions with Timoni’s and Pylarini’s papers in them. The reverend doctor “surreptitiously” employed Douglass’s rival, Dr Boylston, to begin inoculating, in July, 1721, or a few months after the first trials in London. Boylston inoculated 244, whites and negroes, and admitted the deaths of six of them, probably by inhaled infection[912]. But Douglass says:
“The precise number of those who dyed by inoculation in Boston, I am afraid will never be known because of the crowd of the sick and dead whilst inoculation prevailed most, the inoculator and relations inviolably keeping the secret.... Some porters who at that time were employed to carry the dead to their graves say that it was whispered, in sundry houses where the dead were carried from, that the person had been inoculated. I could name some who are suspected, but having only hearsay and conjectural evidence, I forbear to affront the surviving relations. I myself am certain of one more who died ‘after inoculation’ as they express it.”
He then gives the case, which was clearly one of the natural contagion of smallpox acquired at the same time as the inoculation. In the Charleston inoculations of 1738, which were also done in the midst of an epidemic, there is little doubt that the fatalities were mostly from natural smallpox which the inoculated infection had failed to anticipate or prevent. The inoculators were often in that dilemma with their fatal cases: either the inoculation had killed the patient or it had been powerless to keep off the contagion; sometimes they confess the former as an untoward accident, at other times they plead the latter, which appears to me to have been the more usual of the two in a time of epidemic smallpox[913].