Page:Popular Science Monthly Volume 54.djvu/454

record follows the fluctuations of the heat record with as much precision as effect follows cause. The summer heat generally begins about the 20th of June and continues with varying intensity until the 15th of September. Within that period we can select many examples which strikingly illustrate the relations of temperature to mortality. For example, the first heated term of the year before us began on the 19th of June and lasted until the 26th of that month. The two records are as follows:

 

Day.	Temperature.	Mortality.
19th	78°	83
20th	80	100
21st	82	122
22d	80	116
23d	77	104
24th	68	119
25th	65	88

 

On the 28th of June a second heated term began, when the temperature rose to 80°, and continued above that figure until July 5th, a period of eight days. The following is the record, including the temperature in the sun:

Day.	temperature.
	In shade.	In sun.	Mortality.
June 28th	80°	118°	118
June 29th	84	120	163
June 30th	85	124	191
July 1st	88	125	247
July 2d	87	128	351
July 3d	82	120	238
July 4th	84	122	227
July 5th	80	121	184

 

It will be noticed that during the last heated period there was a more prolonged high temperature than during the first, and that the mortality of the second was higher for the same temperature than that of the first. These facts are in accord with the history of our summer months. The range of temperature increases as the season advances, and the rate of mortality rises, owing to the diminished resisting power to the effects of high heat on the part of the people, especially of the children, the aged, and those already enfeebled by disease.

In order to fully understand the influence of heat and its effects upon the public health, we must first notice the conditions regulating the temperature of the body in health and disease.

The temperature of animals in a state of health is not a fixed quantity, but has a limited range which depends upon internal and