On the State of Disease in Sweden during 1862 and 1863

In an epidemiological point of view the chief characteristic of the years 1862 and 1863 in Sweden, was the wide prevalence of measles. The disease began to augment in quantity in 1861. The following year (1862) it became epidemic, and pervaded the whole kingdom. During 1863 the malady declined, so that, after the first six months of the year, it may be considered to have ceased as an epidemic. Whilst the epidemic of measles was diminishing, diphtheria progressively increased, and small-pox began to augment so greatly as to lead to the apprehension of an epidemic extension of the disease. The weather and temperature of the two years was remarkably unlike. During the year 1862 there was an uniform persistent winter, a particularly warm spring, a cool and rainy summer and autumn, while the following year presented an unusually mild winter with very little snow, with uncovered fields, and almost uninterrupted open seas, followed by a rather cool spring and moderately warm but rainy summer, during which, in the midst of the month of July, occurred severe frost, simultaneously observed over the whole kingdom, from Norrbotten to Scania. The autumn, however, continued mild to the close of the year, with frequent storms and much rain. The mean temperature, which during the preceding year was, at the Stockholm Observatory, 40*06? F., in 1863 rose to 45*41? F., the same for the six autumn and winter months being 36*78? F. (in 1862, 29*03? F.), and for the six spring and summer months 53*65? F. (in 1862, 51*13? F.) or calculating each season separately, during winter 34*37? F.; during spring (April and May) 44*06? F.; during summer (June?September) 382 STATE OF DISEASE IN SWEDEN. 58*46? F.; and during autumn 36'62? F. The unusually high mean temperature of 1863 is therefore to be ascribed less to any excessive warmth during the fine time of the vear, than to the circumstance that both the autumn and winter were unusually mild, which may also explain the fact that dysentery and ague, both which diseases might reasonably have been expected to increase considerably both in frequency and extent during a year with so high a mean temperature as that now in question, nevertheless continued so little prevalent.