THE SUMMER HEAT OF CITIES. 



435 



These statistics demonstrate the extreme unhealthfulness of New 

 York during the summer, and the vast proportion of children who 

 perish from the fatal agencies which are then brought into activity. 

 It is a matter of great public concern to determine the nature of 

 the unhygienic conditions on which this excessive mortality depends, 

 and thus discover the proper remedial measures. 



As high temperature is the distinguishing feature of the summer 

 months, we very naturally conclude that excessive heat is a most im- 

 portant factor, if not the sole cause, of the diseases so fatal to human 

 life at this period. A close comparison of the temperature and mor- 

 tality records of any summer in this city demonstrates the direct re- 



lation of the former to the latter. For illustration, we will take the 

 records of the Health Department during the past summer, select- 

 ing diarrhoeal diseases for comparison, as they prevail and are 

 most fatal at that season of the year. The table gives the total 

 mortality from these diseases and the mortality from those diseases 

 of children under five years of age. To the four months, June, July, 

 August, and September, are added May and October, for the pur- 

 pose of showing the gradual increase of the mortality from these dis- 

 eases as the hot weather approaches and its decline as the hot weather 

 abates. 



Again, if we compare the temperature and mortality records for a 

 series of days instead of months, it will be noticed that the mortality 



