June 23, 1881] 



NATURE 



173 



THE WEATHER AND HEALTH 

 OF LONDON'^ 

 II. 

 A N examination of the curve for the 

 -'*• whole mortality (Fig. 4, Nature, 

 vol. .xxii. p. 144) shows that the great 

 preponderance of deaths in London 

 takes place during the coldest months 

 of the year. Uf the diseases to which 

 this excessive mortality is due, the 

 first place must be assigned to dis- 

 eases of the respiratory organs, the 

 more marked of which are given in 

 Figs. 12 to 15. About one in eight of 

 all deaths that occur is caused by bron- 

 chitis, and one in sixteen by pneumonia ; 

 so that nearly one fifth of the deaths is 

 occasioned by these two diseases of the 

 respiratory organs. Our researches ap- 

 pear to warrant the conclusion that the 

 greatest fatality from these diseases 

 occurs when the temperature is between 

 32° and 40°. In New York, when the 

 winter temperature is io'"'o lower than in 

 London, the mortality from bronchitis 

 and pneumonia is greatly less ; on the 

 other hand, in Melbourne, where the 

 winter temperature is about io°o higher 

 than that of London, the mortality from 

 diseases of the respiratory organs forms 

 but a small fraction of the whole deaths. 

 These four curves of the mortality from 

 diseases of the respiratory organs are 

 substantially the same, each having its 

 maximum in the cold months and its 

 minimum in the warm months. Asthma 

 shows, in the amplitude of its annual 

 range, the greatest sensitiveness to 

 weather, and pneumonia the least. They 

 all show, though in different degrees, a 

 double-ridged maximum : the one ridge 

 being in the middle of January, when 

 the temperature falls to the annual 

 minimum, and the other in March, when 

 the combined qualities of cold and dry- 

 ness are at the annual maximum. Asthma 

 and bronchitis are decidedly at the maxi- 

 mmnwhen the weather is coldest, whereas 

 laryngitis has its maximum in March, 

 when the weather is coldest and driest, 

 the last disease thus forming the link 

 connecting the more strictly throat 

 diseases with diseases of the nervous 

 system. 



But an element of weather other than 

 mere temperature plays an important 

 part in bringing about the high death- 

 rate from these diseases. That dele- 

 terious atmospheric influence is fog ; 

 and in cases where the fog is dense and 

 persistent the mortality from diseases of 

 the respiratory organs becomes truly 

 appalling, as happened in London early 

 in 1880, when the mortality was nearly 

 doubled. An examination of the fogs of 

 London shows that they do not com- 

 mence till the autumnal equinox; and it 

 is at this epoch that asthma (Fig. 12), by 

 far the most sensitive of all diseases to 

 fog, starts from its annual minimum; 

 and in the end of November and begin. 



SoD I I 



.30P I I 



Feb. March. April. May. 

 I I I 



-^\ 



June. July. 



MM 



MM 

 Fig. 13. 



LI 1 

 ■Asthma. 



Sept. Oct. Not. Dec. 

 MM Ml III Mir 



r-'t 



Fig. 13. — Cronchiii 



111 



6. — Apoplejcy. 



MM III III I I I 'J 

 I I I I 111 Ml II I q 



• Substance of a 

 Institution, March ;: 



the Royal 

 146. 



