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most violent in the last months of the year, continued into the new year, and died away with the spring. I believe, too, that sporadic cases are most common in autumn, although I have seen such instances in the month of April. Cases, however, occurring in the spring, even though of malignant character, seem to me more likely to recover than at the other seasons.

Sydenham remarks that scarlet fever, though it may occur at other seasons, is most common in the. end of summer, when it attacks whole families, and children especially. Fothergill, in describing the malignant form of scarlet fever, observes :“ Although it survives different seasons, and all varieties of weather to which we are exposed, yet it seems to show itself most frequently in the autumn, and in the beginning of the winter ; at least I have met with more cases from September to December inclusive, than in all the other months together.”

Cullen names the beginning of winter as the time when scarlet fever is most prevalent. Withering speaks of the winter and summer months as favourable seasons, and records the particulars of an epidemic which, commencing in summer, was temporarily checked in October, but recommenced, with extreme virulence, in November. The terrible epidemic of malignant scarlet fever that raged in St. Albans in 1748, is described by Dr. Cotton as occurring in the latter end of the year. The epidemic recorded by Peart in 1802, did not become violent and extensive

until the latter part of August, and in September. Willan remarks that the disease, scarlet fever, is most virulent during October and November. Haygarth entertained a similar opinion. Rayer observes that the disease is most common about the equinoxes. An epidemic of malignant scarlet fever, described by Chomel under the title of gangrenous sore throat, and which raged in Paris a hundred years ago, was most violent in the months of October and November. Dr. Nieuwenhuys, in his paper on “ the scarlet fever in Amsterdam in the year 1834,” remarks, “the disease first showed itself, in the epidemic form, in the month of June 1834, and its victims were-in June 22, in July 32, in August 50, in September 78, in October 136, in November 106, and in December 61.”

Mr. Ryland, in describing the cases of scarlet fever which occurred under his care amongst the outpatients of the Birmingham Infirmary in the year 1835, states that in the first quarter of the year ending March 25th, he had 5 patients, in the second quarter 7, in the third quarter 35, and in the three last months 59, making 106 cases in all.

Finally (many other authors being omitted), Dr. Tweedie, in his essay on scarlet fever, states that the disease is most common in autumn, least so in spring.

Such are some of the conclusions to which general observers have come with reference to the prevalence of scarlet fever at the various seasons of the year; and when these conclusions are tried by statistical facts, their correctness is strikingly established.

In 46,077 deaths from scarlet fever in England in 1841 and 1842, and in London in the years 1838, 1839, 1840, 1843, 1844, 1845, 1846, 1847, and 1848, the proportions of deaths in the seasons of those years run as follows:

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Total.

April, May, July, Aug. Oot. Nov. Jan. Feb.
June. Sept.

March.
No. of deaths... 9,068......11,914......14,630......10,465......46,077
Percentage...... 19.679...... 25.856......31:751...... 22:711

The above table requires no comment. Derived from an immense number of cases, the inference to which it leads, viz., that scarlet fever is most prevalent in this country in the last three months of the year, least so in the months of April, May, and June, is obvious. One word I must add. If the reader could see an analysis of the above tabular statement, he would find that the rate of mortality is not always the same in the special quarters of the years specified. So that a calculation made from one or two, or even three, of those years would be likely to lead into a grievous error. When, however, the trouble is taken to reduce the returns of a great number of years to a single calculation, we approach as near to the truth as absolute knowledge can carry us.

The correctness of these results is, moreover, singularly confirmed by the calculations of Dr. Tripe. In a paper in the Transactions of the Epidemiological Society for 1857, Dr. Tripe takes up the statistics of scarlet fever from 1840 to 1856, as they are recorded in the returns of the English Registrar-General. The

summary of Dr. Tripe's labours in this direction was, as follows:

“Of the total mortality in the years 1840-56, viz., 33,451, 6042 deaths happened in the spring, 7910 in the summer, 11,706 in the autumn, and 7793 in the winter quarters; or in the following ratio, 18.0 per cent. in spring, 23.6 per cent. in summer, 35.2 per cent. in autumn, and 23.2 per cent. in winter. This disease is, therefore, by far more fatal in autumn than in any other season, and, as before shown, rages most furiously from the middle or end of September to the middle of November; the largest number of deaths having occurred in October. I put the percentages in a tabular form.

Percentages of Deaths from Scarlet Fever.
Years.

Spring Summer. . Autumn. 1840-56 ......... 18.0 ...... 23:6 ...... 35.2 ...... 23.2 1840-49 ......... 17:7 ...... 24:8 ...... 35.6 ...... 21:9 1850-56 ......... 18.5 ...... 22:2 ...... 34:3 ...... 25.0 • The variation in rate of death in the quarters of the two periods under examination was much less than in either measles or small-pox. In the spring quarters of 1840-49, the rate was 17.7, and of 1850-56, 18:5 per cent. ; in the summers of 1840-49 it was 24:8, and of 1850-56, 22:2 per cent. ; in the autumns of 1840-49 it was 35.6, and of 1850-56, 34.3 per cent. ; in the winters of 1840-49 it was 21:9 per cent., and of 1850-56, 25.0 per cent. From these data it is evident that the greatest mortality from scarlet fever occurs in autumn, and the smallest in spring. The variation in the rate of mortality was greatest in the winter quarters; for in the winters

Winter.

of 1840-49, out of each 100 deaths, 21:9 per cent. occurred, whilst in 1850-56 no less than 25.0 per cent. happened.

“ The rate of death in the two periods was by no means alike; 1858 deaths having been registered in each year of 1840-49, and 2124 in each of the years 1850-56, being an excess of one-seventh. This has arisen from the disease having assumed an epidemic form at shorter intervals than usual.”

Now, in considering season and its influences, what are we to interpret from it? The term is too wide to be in any degree definite as a cause of disease. What is there in season to determine the origin and modify the course of a pestilence such as scarlet fever ? I confess I am unable to tell; for, when the broad affirmative fact is established, all in the way of detail is negative.

I did, indeed, once with great labour endeavour to analyse the facts bearing on this question. I sought through the meteorological changes of season for an explanation of the prevalence of this one disease at particular periods. Was there anything in temperature, in barometrical pressure, in rain, in the electrical conditions of the air, and, above all, in the movements of the winds, that could influence the course of the disorder ? It was a painful failure, this research ; and I will show it in its failure. After various endeavours to arrive at results which should be to my mind satisfactory, I determined at last to find certain periods when the disease in one given city, say London, should present in a given time, say a

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