596 



NATURE 



[April 24, 1890 



Astronomical Society of France. — The following officers 

 have been elected for the session 1890-91 : — President, M. 

 H. Faye, Member of the Institute. Vice-Presidents : MM. 

 Bouquet de la Grye, Member of the Institute ; Camille Flam- 

 marion, Laussedat, and Trouvelot, of Meudon Observatory. 

 Secretaries : MM. Ph. Gerigny, Armelin, and Bertaux. 



The Society meets at the Hotel des Societes Savants, 28 Rue 

 Serpente, Paris, and there is an Observatory and a Library open 

 to the members. 



D'Arrest's Comet. — The following ephemeris for the 

 search for this periodic comet on its return this year is given 

 by M. G. Leveau in Ast7'. Nach., No. 2959 : — 



Ephemeris for Paris Mean Time. 



INFLUENZA AND WEATHER, WITH SPECIAL 

 REFERENCE TO THE RECENT EPIDEMICS 



T N this inquiry the authors deal only with deaths recorded by 

 the Registrar- General as due to, or caused by, influenza in 

 London between the years 1845-90. The statistics for London 

 are selected because there is there a vast population in a small 

 area, all subject to the same climatic conditions, and because 

 there is also there a weekly record of deaths and their causes 

 for a long period, which they discussed with some fulness of detail 

 some years ago. 



After making allowance for certain errors to which such an 

 inquiry is liable, arising chiefly from the methods of registration, 

 it is found that the figures recorded disclose certain phenomena 

 with such emphasis that the lessons taught by the phenomena 

 stand altogether unaffected. Thus, as regards the distribution of 

 deaths over the year, during the 45 years, the results show a 

 strongly marked winter maximum and an equally marked 

 summer minimum ; along with which there is also a small 

 secondary maximum in the second half of March and first half 

 of April. Thus, broadly considered, the distribution of deaths 

 from influenza is inversely as the temperature, being at the 

 maximum during the winter months when temperature is lowest, 

 and at the minimum in the summer months when temperature is 

 highest. Hence the curve showing the distribution of deaths 

 from influenza is closely congruent with the curve for diseases of 

 the respiratory organs, with the addition of a slight rise in spring, 

 thus suggesting a connection between influenza and diseases of 

 the brain and the nervous system. 



During the last 45 years, 4690 deaths are registered as having 

 occurred from influenza, or 104 per annum. There is no year 

 in which there has not been some deaths recorded as due to 

 influenza; but during the 12 years ending with 1889, the 

 registered deaths have been decidedly fewer than during the 

 preceding 33 years, the mean number for these 12 years being 

 only 6|, falling in some of the years as low as 3. There have 

 been five periods during these years in which the figures point 

 to the prevalence of an epidemic of influenza, the exact periods 

 of which, with the number of deaths registered as due to in- 

 fluenza, are these : — 



Deaths. 



December 1847 to April 1848 1631 



March to May 185 1 258 



January to March 1855 ... ... ... 130 



November 1857 to January 1858 123 



January to March 1890 545 



Total 



2687 



Thus the five epidemics yielded 2687 of the 4690 deaths 

 registered, or about 57 per cent. From a discussion of the 



' Abstract of a Paper, by Sir Arthur Mitchell and Dr. Buchan, read at the 

 half-yearly meeting of the Scottish Meteorological Society, March 31, 1890. 



details of each epidemic and the weather which prevailed during 

 each of them, it was shown that in each case the rise to the 

 maximum was strikingly rapid after the disease was recognized 

 as existing. It was further concluded that the epidemics of 

 influenza in this country were not, though they occurred during 

 the winter, connected with exceptionally cold weather, especially 

 at their commencement, but on the contrary rather with ex- 

 ceptionally warm weather, which manifested itself generally 

 both before and during the epidemic. In no case that has 

 occurred was any exceptionally cold weather intercalated in the 

 period of the epidemic, accompanied with an increase of deaths 

 from influenza, or even with an arresting of the downward 

 course of the curve of mortality, if the cold occurred at the time 

 the epidemic was on the wane. This fact presents influenza 

 under widely different relations to temperature as compared with 

 all diseases of the respiratory organs. 



During the first four weeks of 1890, when the mortality from 

 influenza was at the maximum, the total mortality from all causes 

 was 2258 above the average of these weeks, and of this number 

 influenza only accounted for 303, thus leaving 1955 deaths due 

 to other causes ; and it is here to be noted that during the time 

 there were no weather conditions, such as excessively low 

 temperature or ctense persistent fogs, which could account for 

 this very large increase of the death-rate. It thus became a 

 point of interest to ascertain what the diseases were which had 

 an exceptionally high mortality during the period, and on the 

 other hand whether there had been any diseases with a mortality 

 for the time much under the average. 



The statistics from the various diseases were minutely ex- 

 amined, from which it was shown that those which yielded an 

 exceptionally high death-rate during the influenza epidemic were 

 diseases of the respiratory organs, phthisis, diseases of the 

 circulatory system, rheumatism, and diseases of the nervous 

 system. These diseases, particularly those of the respiratory 

 organs, produced a very large excess above their averages, in 

 spite of the fact that on the whole temperature had been par- 

 ticularly high, and dense fogs absent, which, being contrary to 

 all rule, plainly indicated that during the period something of 

 an exceptional character had been operating to increase the 

 deaths from diNcases of the respiratory organs. The strong 

 manifestation of nervous symptoms in the severe headaches and 

 prostration which attended the attacks of influenza, make the 

 increase of deaths from diseases of the nervous system and of 

 phthisis deeply interesting, as suggestive of a relation to the 

 secondary spring maximum. So, also, the increased number 

 of deaths from rheumatism is interesting in connection with 

 the muscular pains which were .so constant a symptom of 

 influenza. 



The diseases which yielded a mortality under the average 

 during the prevalence of the epidemic were diarrhoea and 

 dysentery, liver disease, measles, scarlet fever, typhoid fever, 

 and erysipelas. It is, however, necessary to remark that the 

 figures refer only to London, and that in other places where 

 epidemics of measles and scarlet fever prevailed at the time 

 these epidemics might show a mortality above the average. 



On the question of age, the point of interest centred in the 

 fact that the death-rate of all persons above the age of 20 

 rose considerably above the average during the four or five 

 weeks immediately preceding the commencement of the regis- 

 tration of deaths due to the epidemic. Thus, though deaths 

 from influenza were not registered in November and December, 

 there appeared to have been something then present, apart from 

 weather, which increased the mortality of all persons above the 

 age of 20 much above the mean. At ages under 20 years, 

 the death-rate rose above the mean only in the first three weeks 

 of the year. 



From a list of twenty-three recorded epidemics of influenza 

 since the year 15 10, it appeared that spring epidemics were more 

 frequent and better marked than they would be if the figures for 

 the past forty-five years were accepted as revealing the whole 

 truth ; and it also appeared that the epidemic of influenza has 

 occurred in early summer and continued to the end of July. 

 Facts, however, are too scanty to show whether the increased 

 mortality during this early summer epidemic extended to the 

 classes of diseases which have their annual maximum mortality in 

 early summer, in a manner similar to the greatly increased 

 mortality from diseases of the respiratory organs or of the 

 nervous system according as the epidemic falls during the winter 

 or the spring months. 



In conclusion it was remarked that in discussions regarding 



