The question most to the front in the influenza of 1803 was its manner of spreading. Beddoes, who believed in personal contagion, had this in view in his five queries:
1. When did the influenza appear and disappear with you?
2. Was its date different in remote places within your reach?
3. After being general, did it occur for some time in single instances?
4. Did it ever seem to pass from person to person?
5. If so, is it likely that clothes or fomites conveyed it in any case?
The dates of commencement were earlier or later according to no rule of direction or of distance from London. In some large towns of Yorkshire it appeared to be unusually late, in Chester unusually early; Edinburgh, certainly, was as long behind London as London was behind Paris. Haygarth, who took the most narrow view of contagion, made out the incidence thus: London first, then the towns which have the greatest intercourse with London, such as Bath and Chester, then smaller towns, and last of all the villages around each of the more populous centres. Several towns had the brunt of the epidemic in the same weeks (of March) as London; in very few was it later than the first weeks of April. In some towns it attracted little notice. In North Devon, it was said to have been at Hartland and Clovelly a fortnight before it was seen in Bideford; the first of it seen by one of the doctors of that town was in a solitary potter’s house four miles to the eastward, on a peninsula made by the confluence of a small stream with the Torridge, all the inmates of the house being attacked; in the town itself from first to last he saw but few cases, whereas there were many in the adjacent country[699].
The general rule seems to have been that the more sparse populations had it later, the nearer they were to the extremities of the kingdom, as in Cornwall, the north of Scotland, and in Ireland. Opinion was divided as to the part played by persons in carrying contagion from place to place, some holding that the facts of diffusion could be explained on no other hypothesis, while most held that the influenza was in the air. Beddoes got as many answers favouring the doctrine of personal contagion as made a respectable show for it; but when these had all been set forth to the best advantage, a practitioner wrote to say that, after all, nine-tenths of professional opinion was against the contagiousness of influenza. The practical question for Haygarth, Beddoes, and other contagionists was whether influenza was not a disease, like smallpox or scarlet fever, which could be kept from spreading by means of isolation, disinfection (with the fumes of mineral acids) and other precautions.
Some curious facts came out, showing the effect of influenza upon other epidemic diseases, or the effect of other epidemic diseases upon influenza. One writer applied to influenza what used to be said of the plague or pestilential fever, that these Leviathan constitutions swallowed up all other reigning epidemics. Holywell, a town in Flintshire, with a large cotton-weaving industry, had not been free from a bad kind of typhus for two years. “On the appearance of the influenza the typhus entirely ceased, and only one case of fever has occurred since. I have not for many years known this country so healthy as since the influenza disappeared[700].” The influenza was said also to have superseded typhus fever at Navan, in Meath[701]. At St Neots typhus was peculiarly prevalent for three months before the influenza, but ceased thereafter[702]. Another relation to typhus was seen at Clifton: “In the low, confined, and ill-ventilated houses in the Hot Well road, where typhus often abounds, the influenza was very unfrequent; while in the exposed high-lying buildings on Clifton Hill it was almost universal[703].” As to ague, which had often before stood in a remarkable relation to epidemics of catarrhal fever, there is one possibly relevant fact related from the Lincolnshire fens. A Wisbech physician writes:
“The influenza which ceased here about the middle of April made its appearance again in May; the leading symptoms were the same as in the first attack. About the same time also a most malignant fever, having some symptoms in common with the influenza, began to rage in that part of Lincolnshire contiguous to us, which has proved fatal to hundreds[704].”