The enormous mortalities of some years may be taken to have depended in part upon an increased prevalence of the disease, but still more upon an increased fatality among the subjects of it. Since the establishment of the Metropolitan Fever Hospitals in 1870 the percentage of deaths to cases has ranged from 15·3 in 1879 to 6·6 in 1873 and 6·7 in 1891. Among the smaller totals of the London Fever Hospital the percentage of deaths has ranged even more widely from year to year[1354]. What is thus statistically proved is also a matter of common experience; there have been whole epidemics, extending perhaps over two or three years, marked by high malignancy, and epidemics just as uniformly marked by mildness of type. The severe type has usually been made by the sloughing in the neck or throat; but there has also been a class of cases tending to a fatal issue early in the attack by a sunken pulse and with few external manifestations. The cause of these variations in the severity of scarlatina is the old problem of epidemic constitutions: sometimes the constitution is “putrid” or “pestilential” or malignant, sometimes it is mild or benign.
Graves, in the passage above cited, has sufficiently exposed the fallacy of attributing changes of type to modes of treatment. On the other hand there is reason to think that the percentage of deaths (by which the “type” is usually judged) is higher in children carried off to hospitals than in those treated at home. As the same fact has been uniformly observed in epidemics of Asiatic cholera, when the ambulances have been almost as busy as those of the Metropolitan Asylums Board during an ordinary autumnal rise of scarlatina, it is probable that the reasons which used to be given in the former case hold good also in the latter.
Scarlet Fever in London, 1890 and 1891.
| Year | All Cases Notified | Treated at Home | Treated in Hospital | Fatalities at Home | Fatalities in Hospital | |||||
| 1890 | 15330 | 8793 | 6537 | 348 or 3·95% | 510 or 7·8% | |||||
| 1891 | 11398 | 6136 | 5267 | 232 or 3·8% | 357 or 6·8% |
This is a comparison of two parts of the same epidemic, which had a very moderate fatality in any case. The real problem of malignity or severity of type arises over such epidemics as those of 1840, 1848, 1858-59, 1868-70 and 1874, in which the doubling of the deaths, for one year, or for two or even three consecutive years, had depended less upon an increased number of seizures than upon a higher ratio of fatalities. An explanation for each occasion will have to be sought either in the condition of the patients, or in the inherent properties or external favouring circumstances of the virus. As to the former, the most fatal epidemic years of scarlet fever have not been marked in any such uniform way as the great seasons of typhus or relapsing fever; nor is scarlatina an infection that keeps mainly within the poorer classes. Among factors of the external kind, a rainfall below the average has been thought a relevant thing: thus in the three years 1862-64, the annual average rainfall at Greenwich was only 20·6 inches, the scarlatina death-rate in London for the same years reaching the high figure of 1·33 per 1000 inhabitants; in the next three years, 1865-67, the death-rate fell to ·56 (it would have fallen in any case), while the rainfall reached the very high average of 29 inches; in the three years following, 1868-70, the death-rate reached the excessive annual average of 1·5 per 1000 in London, the rainfall of the same period averaging only 22·3 inches. Thereafter for a number of years the rainfall was moderate and the scarlatina death-rate low; but in the years 1883-87, they were both low together, the scarlatina death-rate of ·26 being lower than it had ever been since registration began[1355].
Although an empirical correspondence between the great scarlatina periods and a series of dry years has not been made out without important exceptions, hitherto unexplained, yet there is a very obvious correspondence between the great rise of scarlatina deaths in London every year and the season of late autumn, which is the season when the ground-water touches its lowest level or begins to rise therefrom to the high water-mark of spring. Of all the curves of seasonal rise and fall constructed by Buchan and Mitchell from the weekly bills of mortality in London from 1845 to 1874, that of scarlatina is the most decided next to that of infantile diarrhoea, the deaths rising in October and November far above the mean line of the year, and falling farthest below the mean in spring and early summer[1356]. This was an old observation—by Sydenham for the scarlatina simplex of that age, by Willan in the end of the 18th century (one or two spring epidemics being remarked upon as exceptional). It is a very curious fact, and one that is as certain (for London at least) as it is curious. Sydenham explained it by the doctrine of his time, that the favouring things were in the human body, namely, some susceptibility of the humours owing to the heat of the preceding summer; but, according to modern views, it should bring scarlatina into the same class with the soil-poisons of enteric fever, yellow fever and cholera, which are believed to become more rife owing to the greater activity of their respective miasmatic viruses when the pores of the ground are occupied to the greatest depth with air in place of water.
It would be singular indeed if, after all, we should have to include scarlatina among the miasmatic diseases; for it is an exquisite instance of an infection which is passed from person to person, or by the agency of volatile contagion, or by fomites in clothes, bed-linen, house-furnishings and the like. The controversy which has raged so keenly in the past between contagionists and non-contagionists over the instances of plague, yellow fever and Asiatic cholera, would become still more keen over scarlatina—and be still more confused if it were not stated in more correct terms at the outset. What we all find so hard to learn is, that the one way of infection does not exclude the other. Plague was for the most part a miasmatic infection in the air of a plague-stricken town; but it could be conveyed in clothes or bales, while it was prudent to remain not too long in the company of a plague-patient. In like manner contagion from the person was, as Rush said and Blane confirmed, a “contingency” in yellow fever; and there are some authentic cases of Asiatic cholera which cannot well be explained except on the hypothesis of contact with the persons of those sick or dead of the disease. Scarlatina is more contagious than any of these, because it shows so much on the surface of the body and scatters its infective matter into the atmosphere of a room with the fine scales or dust of desquamation. Still, there are conditions for the contagiousness of scarlatina, just as there are for the rarer event of contagion from the persons of the sick in the plague, yellow fever and cholera. It is a remarkable fact that scarlet fever should ever be sporadic, or that a single case should appear in the midst of a crowded population (as I have seen in a coast town filled with strangers during the herring fishery to the extent of one-half more than its usual numbers), and no other cases follow for months after, although there had been not the smallest attempt at isolation. Every medical practitioner knows, if some laymen and legislators do not, that scarlatina is sometimes highly contagious, and sometimes hardly contagious at all; and who can say whether the mechanical routine of “stamping out” contagion, which certain persons pursue with more zeal than knowledge, may not be the means of turning a mere potency into an actuality? The tact of individuals rather than the grinding machinery of an Act of Parliament is needed in dealing with vagaries such as Willan thus describes:
“I have seen in numerous families one child have scarlatina without communicating it to any of the rest; yet, perhaps, in the succeeding autumn, several of them were infected by only passing near a patient recovering from the disease, or by touching those who had a little time before visited some persons affected with it[1357].”
There are two special forms of epidemic scarlatina which may prove to be finger-post instances for the general pathology. It happens from time to time in the surgical wards of hospitals for children, where many cases of suppurating diseases (especially of the bones or joints) are aggregated and kept together perhaps for months, that groups of the patients acquire a scarlet rash, or an erysipelatous rash, or a hybrid form of rash, along with the constitutional symptoms of scarlatina. Whether it be from the suppuration, or from the blood of operations, this disease must be reckoned a product of so-called “hospitalism.” It is not without significance that there may be an element of erysipelas in such cases. They are probably cases of “blood poisoning,” in a double meaning of the term—poisoning of the living blood by dead blood or by pus which is closely allied to blood[1358].
The other special kind of epidemic scarlatina is that which has broken out among the inmates of houses supplied with milk from a common source. There have been many such outbreaks, including one most remarkable instance in which a large number of guests at an evening party, who had partaken of cream with strawberries, were shortly thereafter attacked by scarlet fever at their widely scattered homes. There can be no question that milk, or cream, has been the vehicle of scarlatinal infection. The first hypothesis tried was that of scarlatina on the dairyman’s premises; the effluvia of a scarlatinal patient might have become mixed with the milk. In some instances, it was actually shown that there had been a case or cases of scarlet fever among the dairyman’s children; but there were other instances in which that could not be shown, and it was, of course, possible to refer the cases, where they did occur, to a common cause in the milk used at the dairy and in the milk distributed from it. As more and more outbreaks of the kind came to be investigated, it was indeed made probable that the infection had got into the milk from the cow[1359]. Someone threw out the suggestion that the cow suffered from scarlet fever, the sign of it being soreness of the paps. Without taking seriously so random a hypothesis as that, we find much agreement as to the fact that the cows, to which the contaminated milk has been traced, were affected, one or more of them, with sore paps. In some cases the disease of the teats had been admitted to be the same as cowpox; in other cases that has been denied; in a third variety, a cow has had cowpox on one teat and something else on another. It matters little what name be given to the affection of the cow’s paps. All soreness of the skin of the teats has the same effect so far as concerns the purity of the milk. Unless the milk be drawn off by a catheter (according to a German practice), the paps are necessarily made to bleed by being “stripped”; it has been admitted by milkers that the blood, pus, and scabs are apt to become mixed with the milk; and the discharges from the sore paps have actually been seen, by a scientific witness, to trickle over the fingers of the milkers into the milk-pail[1360]. The contamination of the milk which produces scarlatina in those who use it is neither more nor less specific than that. The disease is blood poisoning in the double sense of the term—poisoning of the living blood by dead blood. Blood is a peculiar fluid, and so is milk. When the two come together the result is peculiar. Both are animal fluids that curdle by some peculiar ferment-change in their constituents. Again, milk is peculiar in its property of taking up organic effluvia; thus the milk standing in shallow vessels has been known to acquire the taste and odour of tar from a tarpaulin in the adjoining farmyard. With such properties of the milk, a small quantity of blood or pus in it will go a long way.