Abstract
The main object of the present research is to discover whether objective signs of physical inefficiency may be found in individuals when subjected to an atmosphere of high temperature and high humidity. Cats were used as the subject of experimentation, and were confined individually for a period of six hours within a small chamber supplied with abundant moving air. With one group of animals the temperature averaged approximately 21° C. and the humidity approximately 54 per cent.; with the other a temperature of 33° C. and a humidity of 89 per cent, were employed; that is, the animals of the first group were kept under comfortable atmospheric conditions, those of the second group were given air approximating that of a hot, humid summer day. In some of the animals the rectal temperature was observed at the beginning and the end of the period of confinement. At the end of this period the cats were taken from the chamber and killed by instantaneous decapitation. The blood was collected for the estimation of sugar, and certain of the muscles were removed and stimulated until they were exhausted, each contraction being recorded graphically and the total duration of the working period and the total amount of work performed being determined. The average results of the observations on the muscles are presented herewith.
Under the influence of the high temperature and the high humidity, therefore, the total amount of work which the muscles are capable of doing before exhaustion sets in is markedly diminished; and the total period of working power is shortened, except in the case of the diaphragm.
The observations show that the bodily temperature of the animals rises in the atmosphere of high temperature and high humidity. This is seen from the following average temperatures.
Get full access to this article
View all access options for this article.