STATES OF THE WIND, AND THE MORTALITY FROM CHOLERA, IN LONDON, DURING THE THREE MONTHS JULY, AUGUST, AND SEPTEMBER, 1849. south-west at the rate of 122 miles a day; and for eight days at the end of August from various points of the compass at the average rate of 81 miles a day; and that, nevertheless, the number of deaths from Cholera continued to increase almost without check from the beginning of July to the 8th of September. In other towns in England, and in Paris likewise, there was the same absence of any fixed relation between the direction of the wind and the degree of prevalence or intensity of the epidemic. These facts are surely not consistent with the theory which attributes Cholera to a general state of the atmosphere or atmospheric influence, if by this theory it is assumed that the cause of the disease is constantly and exclusively in the air, attached to it and moving with it. It cannot be that the persistence of the epidemic in a town was due to portions of such a pestiferous atmosphere being left within buildings or confined spaces, while the great mass was moved away; for even supposing that the air within many buildings were fixed instead of constantly changing, as it is, still a great temporary alteration in the force of the epidemic must have attended or followed a change of the wind. Nor is it possible that the continuance of the epidemic for several months in one place was due to successive portions of the morbific atmosphere being brought at intervals: for, in that case, too, there would have been marked remissions and augmentations of the severity of the epidemic according to the direction in which the wind was blowing. If, then, the epidemic was primarily due to a general state of the atmosphere or to an influence moving with the atmosphere, this state or influence must, it would seem, have determined the production of a more fixed morbific agent in various parts of the country and of individual towns, which remained, and was capable of increase after the transient atmospheric influence had long passed by. But this hypothesis has the defect of assuming two causes as necessary, one serving for the transmission of the epidemic from one country to another, and the other being the efficient cause which really produces the disease in the spots where the epidemic reigns. A more simple explanation of the long continuance of * See the Table of the states of the wind during the epidemic in Paris given in the Appendix, Table III. Cholera, in the countries or towns which it visits, is obviously afforded by the theory of its dependence on a morbific matter, transportable within limits from place to place by the atmosphere, and capable of increase under favourable conditions in the places to which it is conveyed. For there is no difficulty in supposing that such a matter might attach itself to the surfaces of bodies within these places, so as to remain fixed there and even to increase, as long as the favouring conditions continued, quite independently of subsequent changes in the direction of the wind, or, in other words, of subsequent movements and changes of the great mass of the atmosphere. The long persistence of the epidemic is equally in accordance with the theory which refers its introduction into a country or a town, and its diffusion there, to human intercourse. As far as regards that particular character of a Cholera epidemic, which has here been considered, either of these two theories is admissible. But the facility with which these theories explain the continuance of the epidemic, itself almost suggests an objection to them: namely, the objection that they would not account for its ultimate cessation. This, however, is a difficulty, the discussion of which must for the present be postponed. IV. It is a fourth character of Cholera, and an important one, which must now be examined, that the intensity of an epidemic of the disease varies during its continuance in a country or a large city; so that it has periods of little and of great activity, and usually well-marked periods of increase, acme, and decrease. The import of this character of the disease, with regard to the principal theories of its cause, cannot be well estimated until something has been learned of the external circumstances or conditions which attend and apparently determine the increase and the decrease of its prevalence in any place where it exists. And here the first fact to be noticed is, that, although Cholera may begin and continue to exist in any season of the year, it most frequently appears in summer, and attains its highest degree of intensity in the course of the summer or autumn, namely, in some month between May and October. The period of greatest intensity is the present subject of inquiry, and the annexed Table shows that in a majority of instances this coincides with the month of July, August, or September. Amongst the thirty-two epidemics, of which particulars are there given, six produced the greatest mortality in the month of July, seven in August, and seven in September; twenty, in all, in one or other of these three months. And amongst thirteen epidemics in the chief cities of the several countries (New Orleans and New York being taken as the capitals of the northern and southern States of America respectively), eleven were most fatal in one or other of the same months, namely, three in July, three in August, and five in September. But the instances in which the greatest mortality occurred in other months and other seasons, are sufficiently numerous to show that season has no exclusive influence in determining the time of culmination of the epidemic. Out of the thirty-two instances, three epidemics were most fatal in June, three in October, one in April, two in March, two in January, and one in December. Even in the same city the greatest mortality from the disease has, in different epidemics, occurred in different months. Paris, for example, in 1832 suffered most severely in the month of April, and in 1849 in the month of June. While, therefore, the more frequent prevalence of Cholera in an intense degree in the later months of summer and the beginning of autumn, taken in conjunction with the known fact that the disease is so much more fatal in hot than in cold climates, would suggest the probability that temperature has a large share in regulating the severity of the epidemic, other facts tend apparently to an opposite conclusion; and further examination of the matter is here evidently needed to determine the connection really subsisting between the epidemic and temperature. City or Town... Year of epidemic TABLE OF EPIDEMICS OF CHOLERA IN VARIOUS CITIES AND LARGE MORTALITY CAUSED BY THEM DURING THE SEVERAL MONTHS October... December. ::: 150 14 190 September 194 279 424 1 96 477 1 1363 2555 1085 35 9 265 314 1198 5368 1575 253 55 122 276 670 5031 874 835 109 46 298 1 336 337 62 41 32 18 19 24 96 7133350 11 2 21 ::: 49 1 5 62 197 : : 610 577 62 115 203 562 220 141 10 133 114 16 14 5275 14610 4181 1184 387 969 1664 746 1208 183 18463 19184 1174 1206 407 2266 ཌ ནྟཀྑཆེ། ི 942 29 1167 30 entire epidemic.. 37 61 163 236 55 154 69 114 35 30 235 182 61 167 18 42 20 90 19 21 162 82 71 23 41 138 52 16 80 Report of the Commissioners of Health, Ireland: Dublin, 1851, p. 79. Report of the General Board of Health on the Epidemic Cholera of 1848 and 1849. Report by Dr. Sutherland, Appendix, pp. 151 and 160. Rapport sur la Marche et les Effets du Choléra Morbus dans Paris, par la Commission, &c., année 1832, Tableau No. 58; and Rapport sur les Epidemies Cholériques de 1832 et de 1849, &c., par M. Blondel: Paris, 1850, Tableau No. 5. d Die Cholera-Morbus in Köln im Jahre 1849, von Dr. F. Heimann: Köln, 1850, p. 9. • Vergleichende Statistische Uebersicht der in Berlin in den vier Epidemien 1831, 1832, 1837, und 1848, vorgekommenen Cholerafalle, von Dr. W. Schütz: Berlin, 1849, pp. 43-154. Report on the Epidemic Cholera prevailing in the Kingdom of Poland in 1852, by Romain Tchesyrleur, Inspector-in-Chief of the Service of Health, &c., &c. Printed by the General Board of Health, and communicated by the Board to the Cholera Committee. The data extend only to the first four days of September, but the epidemic was then rapidly declining. Rapport sur le Choléra-Morbus, par Alex. Moreau de Jonnés: Paris, 1831, p. 297. The data extend only to the 14th of November, but the epidemic was then beginning to decline. On the 18th of December there were only nine deaths. In January, though the epidemic was not extinct, the number of deaths in a day never exceeded eleven, and was as low as one. |