Chapter V: Measles (2)

In order to explain the enormous increase of deaths by measles, he had
recourse to the following argument. Formerly nearly all children, say
nine-tenths, had both smallpox and measles, the attack of smallpox in
most cases coming first. Children who had survived smallpox were
fortified by that ordeal, not merely as selected lives, but
positively fortified, so that measles, when it assailed them in due
time afterwards, was taken mildly or was “modified,” not one in a
hundred cases proving fatal. But now (1813), when so few children have
been through the smallpox, measles has become ten times more fatal to
them, although it could hardly be more common than it used to be.
Having found it necessary to assume that children in former times took
smallpox before they took measles, nine-tenths of them taking both, he
qualifies this in another passage: “Still, however, as the measles
came round now and then, as a very general epidemic, they must
occasionally have had the precedence, and it was perhaps chiefly among
such patients that the disease proved fatal.”

The measles which came round now and then as a general epidemic was
nearly the whole of it; even in London there were intervals of several
years with only a few annual deaths, and in smaller towns or country
districts the clear intervals were longer. The prevalence of measles
on the great scale being more casual than that of smallpox, it is
likely that most children had taken smallpox before they incurred
measles. But it is clear from such instances as the London epidemic of
1674, and the epidemic in the Foundling Hospital in 1763, that measles
might attack children just before smallpox, and by its weakening
effects, increase the number of victims of the latter. As to the
fatality of measles itself in the 17th and 18th centuries, the
statement of Watt that it did not amount to one death in a hundred
attacks, while it can neither be proved nor disproved by an array of
figures, can be shown to be inconsistent with the language of
annalists. The epidemics of measles varied in severity then as
afterwards: that of 1670 in London was regular and mild, that of 1674
in the very same months of the year was anomalous and fatal; Huxham
characterizes the measles at Plymouth in the winter of 1749-50 as
“maximé epidemici, imo et saepe pestiferi”; at Kidderminster, in 1756,
after fevers had been very fatal to adults, the measles went through
the town so that an immense number of children “died tabid”; in the
West of England about 1760 a disease called measles made “a melancholy
carnage amongst children.”

While Watt’s theory of the working of this principle of substitution is open to criticism on some points of detail, the law itself, as enunciated by him, remains to the present time one of the soundest and most instructive generalities in epidemiology. He based it upon a laborious search of the burial registers, such as no one before him in this country had undertaken. Next he saw correctly that a great rise in the deaths of infants by such a disease as measles could only be accounted for by a great increase in the rate of fatality. Thirdly, he connected the loss from measles with the saving from smallpox. Adopting an old opinion, which may be discovered in Willis[1219], he argued that smallpox, when taken first, served to fortify children so that they passed easily through the measles afterwards; but in the following passage he indicated a better reason why the absence of smallpox gave measles the chance of proving more fatal: “In this point of view we are not to consider the smallpox as so peculiarly fatal in their nature. They perhaps prove so fatal merely by having the start of other diseases. The measles, the chincough, the croup, the scarlet fever, and perhaps many others, would have proved equally fatal had they occurred first.” The principle is true to this extent, that a certain proportion of weakly infants, or children of poor stamina, will succumb to almost any disease--if not to smallpox, then to measles, and if not to measles directly, then to the sequelae of measles. This was perceived in the form of a necessary truth by Haygarth in 1793: “A considerable number of those who now die of the smallpox would die in childhood of other diseases if this distemper were exterminated[1220].” It was commonly believed that smallpox had at length found its real artificial check, not in the inoculation of itself, but in the inoculation of cowpox. At all events it had declined greatly in Glasgow. During the three years before the measles epidemic of 1808, there could hardly have been more than a thousand children attacked by smallpox, or not one in ten of all the children born. During several years the infancy of the city had been spared any great ordeal of infectious disease; the first epidemic that came along happened to be measles, so that it fell to that infection to take off the weaklings. In the economy of nature it is impossible to rear all the young of a species, nor would it be good for the species if it were possible. It is among the birds that the principle of population, or of the survival of the fittest, is seen working in the most admirable way: the annual migration of many species to breed in a remote country brings with it an ordeal for the birds of the year in finding their way to the winter feeding-grounds--an ordeal which only the strongest come through. For some unexplained reason, the young of the human species are peculiarly tried by infectious diseases, which multitudes pass through safely, while many of poor stamina or of ill tending are cut off.

Dr Watt’s teaching, as to the displacement of one infectious cause of
death by another was resisted at the time as being of “evil tendency”
for the pretensions of vaccination, although Watt believed as firmly
in the virtues of cowpox as Jenner himself did. Writing to James Moore
on 6 Dec. 1813, Jenner says of Watt’s essay (Baron, II. 392): “There
is nothing in its title that developes its purport or _evil
tendency_.... Is not this very shocking? Here is a new and unexpected
twig shot forth for the sinking anti-vaccinist to cling to.” Sir
Gilbert Blane, who was then president of the Medical and Chirurgical
Society, having a natural fondness for ideas of all kinds expressed in
a paper to that society rather more approval of Watt’s view than was
thought prudent: “An ingenious friend of mine has remarked to me in
conversation that some light is thrown on this subject by considering
that whichever of the epidemic maladies attack children first, it will
be the most fatal, inasmuch as all feeble constitutions will fall in
its way while the stronger will be left to encounter the attacks of
the others; and that the smallpox, owing probably to the greater
abundance and rankness of their effluvia, are generally caught in a
casual way before measles, hooping cough and scarlet fever, and are
therefore reckoned more fatal than any of these. But, a new field of
research being opened,” etc. Efforts were made to correct the effect
of this, by showing that measles in some parts of the country had not
been more fatal than usual. Holland, of Knutsford, attributed the
fatality of the epidemic in 1808 to a change of the wind to the east.
Writers in the _Edinburgh Med. and Surg. Journal_, pointed out that
Watt had compared the absolute deaths by smallpox at one time and by
measles at another without taking account of the increase of
population, and the rates of mortality from each disease. The best
criticism of Watt was by Roberton in his _Mortality of Children_,
1827, p. 49. He offers the following considerations, without seeming
to know that they were really to be found in Watt’s own essay:
Smallpox used to be caught first; it swept off the feeble and sickly,
leaving the strong and vigorous _only_ to encounter the attacks of
other diseases. “That infectious febrile disease to which in early
infancy there is the strongest predisposition will of course in
general make the first attack and prove the most fatal of any.” There
were reasons why measles used to have comparatively few victims, “and
why, when they now prevail epidemically, they, as was the case with
smallpox, are caught at an earlier age than other diseases in general
and prove so very fatal: which happens not more from their priority in
attack than from being in their nature what they were ever
considered--a severe and dangerous disease. We are to recollect,
however, that measles do not in general attack at so early an age as
smallpox; nor ever, like the latter, destroy eight or nine-tenths of
all the children that die in the place where they happen to prevail,
as was the case in the variolous epidemics of Chester and Warrington
[this is an error, _vide supra_, p. 554]; consequently we have reason
to hope that neither measles nor any other infantile disease will, as
Dr Watt imagined, ‘come to occupy the place which smallpox once
occupied,’” (p. 58). A feeble echo of Roberton’s criticism, with all
its scientific candour left out and its points against Watt emphasized
in a spirit of paltry cavilling, was heard next year in the
Goulstonian Lectures of Bisset Hawkins on _Elements of Medical
Statistics_, 1829.

Many years after, when the enormous increase of deaths by scarlatina
was illustrating the doctrine of displacement in a new way, Dr Farr
gave a full analysis of Watt’s essay in his annual Letter to the
Registrar-General for the year 1867, and endorsed the Glasgow teaching
of 1813 with more heartiness than it had hitherto received. Although
Farr did not take the Malthusian view that the loss of weakly children
by one means or another was inevitable, yet he could not help seeing,
in his work upon the registration returns from 1837 onwards, that one
infection had been taking what another spared. He recurred to Watt’s
doctrine time after time in his annual reports, and in that of 1872
(p. 224), expressed his belief thus plainly: “The zymotic diseases
replace each other; and when one is rooted out, it is apt to be
replaced by others which ravage the human race indifferently whenever
the conditions of healthy life are wanting. They have this property in
common with weeds and other forms of life: as one species recedes,
another advances.”

Two remarks remain to be made under the doctrine of displacement. The first is that the substitution of measles for smallpox was one of a series of such changes in the public health of Britain. The great infective scourge of medieval and early modern periods had been plague, which destroyed at times immense numbers of the valuable or mature lives. Its successor was typhus fever, which also cut off the parents more than the children, but did not retard population as the plague had done. The saving of life by the extinction of plague was in great part balanced by the loss from smallpox, which fell, however, more and more upon the earliest years of life until at length it was almost confined to them. The first great decline of smallpox itself corresponded to a great decline of typhus fever during the second half of the French war; but while there was no great infectious disease in those years to thin the ranks of the adults, measles took the place of the more loathsome smallpox in cutting off a certain number of young lives. While the older types of infection have disappeared, the incidence has shifted from mature lives to children, so much so that at the present time enteric fever, and occasional choleras and influenzas, are almost the only infections that correspond to the old plague and to typhus fever in their age-incidence.

The other remark is that the greater prevalence or fatality of measles, as if in lieu of smallpox, meant a good deal more for the bills of mortality than actually appeared under the name of measles. Smallpox was not an infection that did much constitutional damage to those that came through it, although it sometimes destroyed the vision and spoiled the beauty of the face. On the contrary, it was held by many that the general health was better after an attack of smallpox than before; and, if personal experience can justify an opinion, that ought to be my own view of the matter[1221]. But measles is an infection peculiarly apt to leave mischief behind. The bronchial catarrh, which is an integral part of the malady, and is often the cause of death in the second stage of the attack, may so affect weakly children that the respiratory organs are permanently damaged. Tuberculosis of the lungs is apt to follow measles. Some children, again, fall into mesenteric disease after measles, and die tabid, the intestinal catarrh being as dangerous in one way as the bronchial is in another. Another large proportion of the subjects of measles take whooping-cough[1222]. While smallpox did its work summarily, the full effects of measles were longer in being realized. This may in part explain the fact brought out by Watt, that while fewer children died under two years of age, measles being the dominant epidemic disease, there was an increase in the ratio of deaths from all causes between the years of two and five and from five to ten.

Measles in the Period of Statistics.

The history of measles for nearly a generation after the great epidemics of 1808 and 1811-12 is little known. No one in Glasgow continued Watt’s laborious tabulation of the causes of deaths in the numerous burial registers[1223]; nor was any regular account kept elsewhere except by the Parish Clerks of London. The following deaths by measles in their bills from 1813 to 1837, when the modern registration began, were probably no more than from a third to a half of the deaths in all London:

Measles
Year deaths

1813 550
1814 817
1815 711
1816 1106
1817 725
1818 728
1819 695
1820 720
1821 547
1822 712
1823 573
1824 966
1825 743
1826 774
1827 525
1828 736
1829 578
1830 479
1831 750
1832 675
1833 524
1834 528
1835 734
1836 404
1837 577

The inadequacy of these figures to the whole of London will appear from the fact that the registration returns under the new Act gave for the last six months of 1837 the measles deaths at 1354, while the bills of the Parish Clerks gave them at 577 for the whole year. But the old bills enable us to compare the deaths from different diseases within the same area and under the same system of collection, and to compare the deaths “within the bills” in a series of years since the last of the new parishes were taken in about the middle of the 18th century. Using the bills so far legitimately, we find that measles at length came to be of equal importance with smallpox itself as a cause of death in childhood, and that it had become a larger and steadier total from year to year.

So far as concerns Glasgow, the high mortality from 1807 to 1812, making 10·76 on an annual average of the deaths from all causes, was not maintained. When the tabulation of the causes of death was resumed from 1835, the annual average of measles for the five years ending 1839 was found to be only 6 per cent. of the deaths from all causes, the average of smallpox having come back to 5·3 per cent. During that unwholesome period, in which there was much distress among the working class and a great epidemic of typhus, measles and smallpox were dividing the infectious mortality of childhood somewhat equally, the age-incidence of measles being only a little lower than that of smallpox:

_Ages of the Fatal Cases of Measles in Glasgow, 1835-39_[1224].

Under one 1-2 2-5 5-10 10-20 20-30 30-40 40-50 Total

1835 116 141 121 34 10 4 - - 426
1836 86 209 183 38 1 1 - - 518
1837 77 133 122 16 2 1 350
1838 76 124 161 39 3 1 1 405
1839 165 259 275 73 7 2 1 783
--------------------------------------------------------
520 866 863 200 23 9 1 1 2482

In Limerick, which may stand for a typically unhealthy Irish city in the worst period of over-population, there were many more deaths from smallpox among children than from measles, the age-incidence being nearly the same, according to the following dispensary statistics for a number of years before 1840[1225]:

_Limerick Dispensary Deaths._

Age 0-5 5-10 10-15 15-20 Total

Smallpox 333 55 5 0 393
Measles 187 32 6 1 226
Scarlatina 8 2 10

Although it is impossible to prove it, yet the indications all point to measles having kept for a whole generation after 1808 the leading place among infantile causes of death which it then for the first time definitely took[1226]. Almost the only direct references to the subject were made by way of controverting the doctrine of Watt; but these are too meagre, or too general in their terms, to be of any use[1227]. The epidemics of measles seem to have travelled then, as they do now, from county to county in successive years. Thus in 1818, while most parts of England were or had recently been suffering from smallpox, the Eastern counties were suffering from measles “very frequent and fatal.” Smallpox at length reached Norwich in 1819, and became the reigning epidemic in the place of measles, which was “hardly met with” so long as the enormous mortality of the other disease proceeded[1228]. At Exeter in the spring of 1824 measles became epidemic after a long interval; many susceptible children had accumulated, and of these few escaped. The mortality was very great, and was caused by severe pulmonary inflammation, the catarrhal symptoms being mild. In one day seventeen children were buried in one of the five parish churchyards of the city; but that high mortality, according to the parochial surgeon, did not on an average stand for more than four deaths in one hundred cases[1229].

When the curtain rises, in the summer of 1837, upon the prevalence and distribution of diseases in England, as ascertained by the new system of registration of the causes of death, measles is found in the first place among the infectious maladies of childhood, thereafter yielding its place to smallpox for a year or more, and taking the lead again until it was passed by scarlatina.

_Deaths by Measles and Smallpox in London, 1837-39._

1837 1838 1839
3rd Qr. 4th Qr. 1st Qr. 2nd Qr. 3rd Qr. 4th Qr. (four quarters)

Measles 822 532 173 96 94 225 2036
Smallpox 257 506 753 1145 1061 858 634

The epidemic of smallpox hardly touched the Eastern counties until 1839; so that while the home counties in that year had far more deaths by measles than by smallpox, Norfolk had only 72 deaths by the former against 820 deaths by the latter. In the same year measles took the lead in four out of six great English towns, scarlatina being the dominant infection in one (Sheffield), and smallpox in one (Bradford):

_Deaths in 1839 by the three chief infections of Childhood._

Liverpool Manchester Leeds Birmingham Sheffield Bradford

Measles 401 773 383 170 33 70
Scarlatina 374 264 35 133 419 7
Smallpox 259 237 171 56 16 208

In all England and Wales during fully half-a-century of registration, measles has fluctuated somewhat from year to year but has not experienced a notable decline among the causes of infantile mortality (see the table at p. 614). In the decennial period 1871-80, its annual average death-rate was 377 per million living; in the next decennium it rose to 441, the previously high rates of scarlatina having fallen greatly. Among the highest rates for the ten years 1871-80, were those of Plymouth, 1·13 per 1000, East Stonehouse 1·79, and Devonport 1·19 (owing to a great epidemic in 1879-80), Exeter, 0·82, Liverpool ·91, Bedwelty (Tredegar and Aberystruth collieries) 0·88, Wigan 0·74, Whitehaven 0·71, Alverstoke 0·81. In the most recent period there have been some very high death-rates; thus at Jarrow the annual rate, which was only ·27 per 1000 from 1871 to 1880, rose in the nine years 1881 to 1889 to an annual average of ·94, having been made up almost wholly by great epidemics every other year--in 1883 (2·9), 1885 (2·4), 1887 (1·4), and 1889 (·9)[1230]. In the year 1888, an epidemic at Stoke-on-Trent, Hanley, &c. with 342 deaths, made a rate of 2·8 for the year; in Wolstanton, Burslem, &c., 221 deaths were equivalent to a rate of 2·6.

The latest reports of the Registrar-General have traced a progression of the epidemic of measles from county to county or from district to district in successive years, such as was remarked, both for smallpox and measles, by some of the 18th century epidemiologists in England, Scotland and Ireland.

Thus in 1890, measles was epidemic in Cheshire, South Lancashire and
North Staffordshire; in 1891 it ceased in these, but became epidemic
in North Lancashire, South Staffordshire and the West Riding; in 1892
it ceased in its last-mentioned area, and became epidemic in
Warwickshire, Leicestershire, Derbyshire, the East and North Ridings,
Westmoreland and Durham. During the same three years a similar
progression or cycle was observable (on looking over the tables) in
the South-west of England. The epidemic year of measles in Devonshire
was 1889. It ceased there, and became epidemic in 1890 in Cornwall on
the one side and in Somerset on the other, sparing Dorset. In 1891 it
ceased to be epidemic in those parts of Cornwall and Somerset which it
occupied in 1890, and became prevalent in the extreme west of
Cornwall, in parts of Somerset, in Wiltshire and in Gloucestershire.
In 1892 it ceased in all the last-mentioned excepting Gloucestershire,
and became epidemic in Dorset, where there had been no severe
prevalence of measles since 1888[1231].

Measles has no such decided preference for a season of the year as scarlatina and enteric fever have for autumn or infantile diarrhoea has for summer. But it often happens that most deaths are recorded from May to July, owing, doubtless, to the greater number of attacks in summer and not to any excessive fatality of that season. In London and the great industrial towns the deaths are spread somewhat uniformly over the year; or, in the language of statisticians, the maxima do not rise far above the mean of the year. In a tabulation of the weekly deaths in London from 1845 to 1874[1232], it appears that they touch a higher point in mid-winter (Nov.-Jan.) than in summer, a fact which may be readily accounted for by the injurious effects of the London air in winter upon a disease which is largely a trouble of the respiratory organs. In the great industrial populations of Lancashire, which resemble London in their high death-rate from measles, the rise of the deaths in mid-winter is almost the same as the summer increase[1233].

Most of the deaths from measles fall at present upon the ages from six months to three years, just as they did when the deaths were comparatively few, as at Manchester from 1768 to 1774. Deaths of adults, which were not altogether rare in the first great epidemic of modern times in 1808, are seldom heard of at present, for the same reason that adult deaths used to be uncommon in smallpox, namely, that the disease is passed by almost everyone in infancy or childhood. Although the deaths from measles sometimes reach large totals--in London during the spring of 1894 they were in some weeks as high as one hundred and fifty--yet it is the common experience of practitioners that a strong or healthy child rarely dies of measles, that the fatalities occur among the infants of weakly constitution, and especially in the numerous families of the working class in the most populous centres of mining, manufactures and shipping.

To bring these various characteristics of measles together in a concrete instance, I shall give briefly the facts of a recent epidemic in a town in Scotland of some twelve thousand inhabitants. There had been only five deaths from measles for two years. There had not been a case of smallpox for at least ten years. The measles epidemic, when its triennial opportunity came, reached a height in July, on a certain day of which month there were seven or eight burials from measles or its direct sequelae. Nearly all the children in the place who had not been through the measles in the corresponding epidemics of 1889 or 1887 suffered from it on this occasion, excepting the class of very young infants. The deaths in the whole epidemic numbered about fifty, which would not all be registered, however, as from measles. Yet this high mortality was not due to any unusual malignancy of the disease, but to the feeble stamina of a certain number of infants, or to the indifferent housing and tending of the poorer class. One did not hear of a death in the well-to-do families (probably there was none), although they had their full share of attacks. The frequency of the burials for a short time, and the effects of the epidemic on the mortality from first to last, must have been very nearly the same as in an epidemic of smallpox a century before, when the population was only a third or fourth part as large. But in the period when smallpox was in the ascendant, having few rivals among the infective causes of death in childhood, the general conditions of health in this town were altogether different. One or two specimens of the thatched huts of the poorer class had been left standing into the era of photography, so that we could compare past with present, in externals at least; also, of the houses of the richer class some still remained, perhaps turned into tenement-houses, with small windows, low doorways, and crow steps on their gables; and it was on record by the parish minister at the end of the 18th century, that within the memory of that generation there had been peat stacks and dunghills before the doors on the High Street of the burgh.