Conditions Favouring Diphtheria.
The circumstances of the great and sudden explosion of diphtheria in 1858 and 1859 are as likely as any to throw light on the causes or determining conditions of the disease. Those two years were remarkable for the Thames running so low in summer as to give out a stench, which was thought to forebode much fever[1379]. The expected epidemic of fever did not come; on the contrary the fever deaths in London were much lower than usual in 1858 and 1859, and, to judge from the few admissions of each kind to the London Fever Hospital, enteric fever declined as well as typhus[1380]. It was diphtheria that came. The lowness of the rivers was due to a succession of years with rainfall below the average:
| Low rainfall | High rainfall | ||||||||
| 1855 | 21·1 | inches | 1865 | 29·0 | inches | ||||
| 1856 | 22·2 | " | 1866 | 30·7 | " | ||||
| 1857 | 21·4 | " | 1867 | 28·4 | " | ||||
| 1858 | 17·8 | " | 1868 | 25·2 | " | ||||
| 1859 | 25·9 | " | 1869 | 24·0 | " | ||||
| Average | 21·7 | " | Average | 27·4 | " | ||||
The low state of the rivers was an index of a low level of the ground-water. If diphtheria is to be included among the infections that have the habitat of their virus in the soil, it will probably be found to be affected by irregularities in the movements of the subsoil water. A series of observations have been made which seem to favour that hypothesis.
At Maidstone in each of the three years 1885, 1886 and 1887, the ground-water rose with the greatest regularity and steadiness to its highest point towards the end of the first quarter of the year, and fell with equal steadiness to its lowest point in the autumn. During two of the years there was little diphtheria, and in one of them none. But, in the next two years, 1888 and 1889, “the levels of the ground-water oscillated to and fro with unwonted frequence,” having several maxima in 1888, and a somewhat uniform high level all through 1889; and during those two years there was a severe outbreak of diphtheria, as well as an excessive number of deaths registered as “croup[1381].”
The relationship with the ground-water, if any, will probably be found to be more than ordinarily complex; but some connexion is indicated by the remarkable selection of the Fen country of Lincolnshire in 1858. Among the 18th century observations, it was remarked in New England in 1735-36 that the throat distemper was worst near lakes or rivers, as at Newbury Falls, Hampton Falls, and the like. The ill-reputed “Kidderminster sore throat,” was associated with the low situation of weavers’ houses in the valley of the Stour, subject to inundations. Practitioners in many parts of England and Scotland have suspected an association with water, even if it were only a mill dam, in the more recent prevalence of diphtheria[1382].
Diphtheria has affinities in its pathological nature with enteric fever on the one hand and with scarlatina on the other. The process in the throat and pharynx is comparable to the typhoid process in the ileum, which is often a truly diphtheritic process in the second half of the fever[1383]. The affinities to scarlatina are shown best of all in the real ambiguity of diagnosis in some whole epidemics of the 18th century, if not also in the great epidemics of garrotillo in the 16th and 17th centuries. Another singular affinity both to scarlatina and to enteric fever lies in the fact that diphtheria, as well as each of these, has been distributed in milk from some particular dairy, and that contamination of the milk by the products of disease upon the cows’ teats has been found to be the relevant thing both for the scarlatina and the diphtheria[1384]. Again, whatever suspicion pertains to slaughter-houses or animal offal for the production of a scarlatinal miasm, pertains to them also for the diphtherial. With such more or less real affinities in the pathology and etiology, it may be made a question whether the recent increase of the death-rate by diphtheria in London and some other places has depended, as if in the way of correlation, upon the decrease in the death-rates of scarlatina and of enteric fever[1385]. Diphtheria is perhaps the most obscure and complex of all the infective diseases in its causes and favouring conditions. A certain explanation may seem to suit one outbreak and be wholly irrelevant for another. More particularly there have been innumerable cases for which insanitary surroundings cannot be alleged in any ordinary meaning of the term.
CHAPTER VIII.
INFANTILE DIARRHOEA, CHOLERA NOSTRAS, AND DYSENTERY.
Infantile diarrhoea and the cholera nostras of adults are closely allied in symptoms and pathology, but they are so unlike in their fatality that they are best considered apart. Dysentery is sufficiently distinguished from choleraic disorders even in nosological respects; and except in Ireland, where its history (already given) has been somewhat special, it might have been made the subject of a separate chapter in British epidemiology. But, for the same reason as in the case of influenzas and epidemic agues and of scarlatina and diphtheria, it is necessary in a historical review to include infantile diarrhoea, cholera nostras of adults, and dysentery in one chapter, the reason being, that they are not clearly separated in the earlier records. So little are they separated in the London bills of mortality that the younger Heberden, in his fragment upon ‘The Increase and Decrease of Diseases[1386],’ has understood the name of “griping in the guts,” under which enormous totals of deaths are entered in the bills for many years of the earlier period, to mean dysentery alone: having assigned that meaning to the name, and having observed, as everyone must, the very palpable fact that “griping in the guts” steadily declined in the bills from the end of the 17th century until it had almost disappeared from them in his own time, he has elaborately proved from the figures that dysentery was at one time among the most important causes of death in London, that it declined in the most regular way, and at length became all but extinct. This illustration of the increase or decrease of diseases has seemed so apt, the statistical demonstration so complete, that it has become a favourite example of those broad contrasts between the public health of past and present times which are not less pleasing in rhetoric than they are on the whole true in fact[1387]. But it happens that the particular instance is wholly fallacious and erroneous. It was not dysentery that the article “griping in the guts” meant for the most part, it was infantile diarrhoea; which has not only not ceased in our own time, but is commonly believed to be distinctively a product of the industrial town life of the present age. I shall show that it was one of the most important causes of London mortality from the Restoration onwards, and that although it is still one of the great causes of death in infants, yet that it had weekly mortalities in some of the hot summers of former times which were far higher in ratio of the numbers living than the diarrhoeal death-rates of our own time. So far as concerns dysentery itself, it is indeed now rare in England and Scotland, and not common in Ireland; but the real history of its decrease has been altogether different, both in the period of it and in the extent of it, from what Heberden supposed. There are two reasons for the fallacy and error of that writer: the first, that he overlooked the question of age-incidence in “griping in the guts”; the second, that he failed to observe that enormous annual totals of deaths under that head had been gradually transferred in the bills of the Parish Clerks to the head of “convulsions,” until there were only a few of the old name left[1388].