Phil Trans. (Abridgement Series, 1809) vol.18 (for 1796-1800), pp.1-3: (Note: originally at Phil. Trans. vol.lxxxvi (1796), at p.279.)
XI. Of the Influence of Cold on the Health of the Inhabitants of London. By Wm. Heberden, Jun., M.D., F.R.S. p.279.
The extraordinary mildness of last Jan. (1796) compared with the unusual severity of the Jan. preceding, affords a peculiarly favourable opportunity of observing the effect of each of these seasons contrasted with each other. For of these 2 successive winters, one has been the coldest, and the other the warmest, of which any regular account has ever been kept in this country. Nor is this by any means an idle speculation, or matter of mere curiosity; for one of the first steps towards preserving the health of our fellow-creatures, is to point out the sources from which diseases are to be apprehended. And what may make the present inquiry more particularly useful, is that the result, as I hope clearly to make appear by the following statements, is entirely contrary to the prejudices usually entertained on this subject. During last Jan. nothing was more common than to hear expressions of the unseasonableness of the weather; and fears lest the want of the usual degree of cold, should be productive of putrid diseases, and I know not what other causes of mortality. On the other hand, "a bracing cold," and "a clear frost," are familiar in the mouth of every Englishman; and what he is taught to wish for, as among the greatest promoters of health and vigour.
Whatever deference be due to received opinions, it appears to me however from the strongest evidence, that the prejudices of the world are on this point at least unfounded. The average degrees of heat on Fahrenheit's thermometer kept in London during the month of Jan. 1795, was 23° in the morning, and 29°.4 in the afternoon. The average in Jan. 1796, was 43°.5 in the morning, and 50°.1 in the afternoon. A difference of above 20 degrees! And if we turn our attention from the comparative coldness of these months, to the corresponding healthiness of each, collected from the weekly bills of mortality, we shall find the result no less remarkable. For in 5 weeks between the 31st of Dec. 1794 and the 3d of Feb. 1795, the whole number of burials amounted to 2823; and in an equal period of 5 weeks between the 30th of Dec. 1795 and the 2d of Feb. 1796, to 1471. So that the excess of the mortality in Jan. 1795 above that of Jan. 1796, was not less than of 1352 persons. A number sufficient surely to awaken the attention of the most prejudiced admirers of a frosty winter. And though I have only stated the evidence of 2 years, the same conclusion may universally be drawn; as I have learned from a careful examination of the weekly bills of mortality for many years. These 2 seasons were chosen as being each of them very remarkable, and in immediate succession one to the other, and in every body's recollection.
It may not be impertinent to the objects of this Society, without entering too much into the province of medicine, to consider a little more particularly the several ways in which this effect may be supposed to be produced; and to point out some of the principal injuries which people are liable to sustain in their health from a severe frost. And one of the first things that must strike every mind engaged in this investigation, is its effect on old people. It is curious to observe among those who are said in the bills to die above 60 years of age, how regularly the tide of mortality follows the influence of this prevailing cause: so that a person used to such inquiries, may form no contemptible judgment of the severity of any of our winter months, merely by attending to this circumstance. Thus their number last Jan. was not much above 1/5 of what it had been in the same month the year before. The article of asthma, as might be expected, is prodigiously increased, and perhaps includes no inconsiderable part of the mortality of the aged. After these come apoplexies and palsies, fevers, consumptions, and dropsies. Under the 2 last of which are contained a large proportion of the chronical diseases of this country; all which seem to be hurried on to a premature termination. The whole will most readily be seen at one view in the following table.
Week ..Mean heat. Whole N° . Aged . ..Asthma. Apoplexy; Fever. Consump- Dropsy. ending. . . . . . of deaths. above 60. . . .. and palsy. . . . tion. .. . . Morn. Noon.