1881.] 



on the Weather and Health of London. 



641 



Tho curve for tlio whole mortality (Fig. 4) shows September 

 and October to be two of the healthiest months of tlie year. Tho 

 three curves, scarlet fever (Fig. 2G), typhoid (Fig. 27), and diphtlieria 

 (Fig. 28), are tho most striking exceptions to this, these curves all 



Fig. 26. 



Scarlet Fever. 



Fig. 27. 



I I 

 Typhoid Fever. 



Diphtheria. 



indicating either a large increase in the death-rate or a high mortality 

 during these months. While closely related to each other, each of 

 these three diseases has a distinct individuality of its own as regards 

 the times of occurrence of the annual maxima and minima, and 

 the varying amplitudes of their range from the mean line. It 

 is a singular circumstance that diphtheria shows closer relations in 

 its death-rate with typhoid than with scarlet fever. 



Several other diseases suggest close alliances with each other 

 through their seasonal death-rates. Thus the curve for mortification 

 is substantially that of nervous diseases, and the curves for erysij>elas 

 and puerperal fever are in all essential respects the same, a fact of 

 singular suggestiveness to the family practitioner. The curve for old 

 age runs exactly parallel to that of paralysis, the old man's disease. The 

 curves for skin diseases, rheumatism, dropsy, pericarditis, Bright's 



