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John Roberton, Observations on the Mortality
and Physical Management of Children

Part I, Section VIII

On the Rate of Infantile Mortality at Different Seasons of the Year

Ever since the days of Hippocrates, and probably before, the seasons have been supposed to exert considerable influence on the physical condition of the body, and each season an influence peculiar to itself. "Spring," says Celsus, "is the most healthy, Winter the next in salubrity, Summer less healthy than either, Autumn the most perilous of all." In the present day, the same opinions generally prevail, erroneously, there can be no doubt, as regards the latitudes of Britain, though they are still applicable, perhaps, to the climate of Italy.

After all, the influence of season in our own country is somewhat uncertain, and not of the importance usually attached to it. In the same town or district, we often find the rate of mortality to vary greatly, in the same months of different years, which obliges us, when we draw any general conclusion on the subject, to take care that it be on an average of many successive years.

The causes of this variation and uncertainty are obvious; they depend not only on the nature of our climate, but also on various local and temporary circumstances. In times of prosperity and plenty, when all have the means of comfortable living, and defence from the rigour and vicissitudes of the seasons; or, when the reverse is the case, as respects the lower classes; the mortality in Winter for instance will be modified accordingly, irrespective, in a considerable degree, of its severity or mildness.

Again, in this climate, infectious diseases prevail at all seasons; and when they rage epidemically, often raise the mortality highest in those very months in which it would otherwise be lowest.

There is a popular adage, "a green Winter makes a fat church yard;" the soundness of which, out of the profession, is universally credited. Of late years several Physicians of eminence [1] have condescended to prove its incorrectness. Their success, however, has been but indifferent. In a paper by Dr. Heberden, first published in the Philosophical Transactions, and since made part of a separate work, the fatal effects of intense cold, particularly on the aged and the very young, are treated of and illustrated in an interesting manner. But the truth or incorrectness of the adage is not to be settled by facts of this description, which no persons, I suppose not even the vulgar, ever disputed.

It appears, according to Dr. Heberden, that the month of January in the year 1795 was the coldest, and the same month in the following year the warmest, that are known to have been experienced in this country. In the former, the number of deaths in London was 2823, of which 717 were above 60 years of age; and 617 infants under 2. In the following January, the total number of deaths was only 1471; 153 above 60, and 506 under 2 years old. This difference in the rate of mortality in the same months of two successive years is abundantly striking. In the first period (that for 1795) the mean morning heat for five weeks was 23°, and the mean noon heat 29°: in the following year and same month, the mean morning heat was 44° and the mean heat at noon 50°. These circumstances, as Milne [2] justly observes, were favorable for determining in which way intense frost affects the mortality in London: "but in comparing the mortality of the severe with that of the mild Winter, one consideration appears to have been entirely overlooked: many infirm persons, no doubt, who had arrived at the brink of the grave in January 1795, and might have lingered there a year or two longer, with mild Winters and the favorable circumstances that attend them, were precipitated into it by the severe frost which took place then, and by the privations they had to suffer in consequence of it. There would, therefore, be fewer persons of that description among the living in 1796 than ordinary; and if the cold then had been as intense as in the January preceding, it would not have occasioned so great a mortality. On this account, the effects both of temperature, much above and much beneath the usual average of our Winters, must be greatly magnified in the comparison above." As a proof of this Mr. Milne shews that in the first 5 weeks of 1794, when there was hardly any frost, and with the average price of breat little more than one-half what it was in the corresponding part of the year 1796, the total number of deaths was nearly twice as great in the former as in the latter year; the number of deaths of persons above 60 years old, more than three times as great, and the deaths of children under 2 years, greater even than during the same period in the severe frost of 1795.

My limits forbid me to follow his train of reasoning in illustration of this interesting subject, which strikes me as being clear and satisfactory; but the conclusion which he draws is this: admitting that intense frost increases the general mortality in London, which it does; 1st, by affecting the great number of infirm and sedentary persons that are to be found in a large city; 2ndly, by raising the price of fuel and almost every necessary of life; and 3dly, by preventing sufficient ventilation, and by that means favoring the spread of contagious diseases; yet it does not therefore follow that a moderate degree of cold, such as we have in England in the depth of Winter, augments the general mortality. On the contrary, an open Winter, attended with sudden changes of temperature, is upon the whole more fatal than a frosty Winter of ordinary severity.

The correctness of this conclusion is shewn by tables of mortality which illustrate the subject. In Sweden, where the cold of Wintoer much surpasses ours, the mortality is not greatest in the depth of Winter, but in March, April, and May, when the weather is doubtless most unsettled.

In England the results of observations made at 25 distant places give the maximum of mortality as occurring in the Spring, and the maximum of that season in April. In July and August the mortality is at its minimum for the year. Indeed there can be no doubt that, what in Scotland is called blashy weather -- that which is upon the whole cold, but characterized by frequent changes in the degrees of temperature and moisture, induces the highest rate of mortality; or, in other words, that in general the popular adage is correct.

Of course these remarks do not apply to all countries. They are intended only for our own.

In regard to the influence of seasons on the mortality of children, it can neither be easily ascertained, nor very correctly estimated. The infectious diseases of children are very numerous and prevail endemically at all times of the year; so that the rate of mortality will be greatly modified by them. On other accounts, it does not exactly coincide with that of the population in general; as we shall presently see. In London, the deaths under 10 are at their maximum in Autumn; which, as respects the morality at all ages, is different. This is no doubt owing to the great prevalence of bowel complaints to which, in autumn, the young are so liable.

The following Table is for London; and embraces 15 years of its Mortality Bills. The seasons are placed not in the usual order, but in the order of their mortality.

LONDON TABLE

Season

Under 2

Between 2 and 5

Between 5 and 10

Total under 10

Autumn

40,079

9,067

3,528

52,674

Spring

37,962

9,356

3,710

51,028

Winter

36,922

8,600

3,772

49,294

Summer

33,694

9,156

3,703

46,553

In the Glasgow Table, [3] for 30 years, the order of the seasons, as to their rate of mortality, differs from the above; and may perhaps be accounted for by the different latitude of the two cities. The Winter in Glasgow is certainly more severe and changeable, and Summer and Autumn are cooler, than in London; which may explain why the infantile deaths are in the former more numerous in Winter rather than in Autumn. But, as was before observed, the course of infantile epidemics, which, if at all affected by season, is so in an uncertain degree only, disturbs and perhaps invalidates our best calculations on the subject.

GLASGOW TABLE

Season

Under 2

Between 2 and 5

Between 5 and 10

Total under 10

Winter

5,763

2,134

630

8.527

Autumn

5,146

1,410

434

6,990

Summer

4,611

1,713

567

6,891

Spring

4,445

1,569

684

6,698

It may be laid down as a rule that when the rate of mortality is very high in a particular season, it will be low in that which follows. Here we see the number of deaths in Winter is so high as 8827, and in Spring so low as 6,698, a difference which no doubt depends on the comparatively small amount of feeble children remaining alive at the beginning of the latter season.

The number of deaths occurring in the seasons will determine, or at least considerably influence the rate of their mortality. In Liverpool, during 13 years, I find the amount of births to be in the following proportions: --

Autumn

15,567

Summer

14,934

Winter

14,771

Spring

13,963

Here we have the births at a maximum in Autumn. Whether the rate of infantile mortality is in the same ratio I have not at present the means of determining, but have no doubt it would be found to be so. The point, though of no great importance, is worthy of investigation. [4]

 

Footnotes

[1] Heberden, on the increase and decrease of diseases; Bateman, on the diseases of London; Willan, on the diseases of London; Woolecombe, on the increase of certain diseases, &c.

[2] Milne on Annuities &c.

[3] Compiled for the mortality bills for that city, published by Dr. Watt.

[4] We are to recollect, in considering this subject, that the rate of fecundity, in the different seasons, is scarcely the same in any two countries. It is influenced by many circumstances, most of which will readily occur to any reflecting mind.


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Created 12/18/96 / Last modified 12/19/96
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