200 PHYSIOLOGY AND HEALTH. 



worked in the open air, the temperature of which was 00 

 Fahrenheit. The barometer was 29 25' to 29 4'." 



474. These eight men lost, during these three fourths of 

 an hour, by perspiration from the skin, various quantities. 



The first lost 2 Ibs. 8 oz. 

 second, 2 " 9 " 

 third, 2 " 10 " 

 fourth, 3 " 6 " 



The fifth lost 3 Ibs. 12 oz. 

 sixth, 3 " 14 " 

 seventh, 4 " 2 " 

 eighth, 4 " 3 " 



The average loss of all was 3 Ibs. 6 oz.* 



475. This constant perspiration, and the exhalations from 

 the lungs, maintain the permanency of the weight of man ; 

 so that, although he eats and drinks from four to six pounds 

 a day, his body at night weighs no more than on the day 

 before ; and, if one man eats and drinks more than another, 

 he has more pulmonary and cutaneous excretions, and the 

 superabundance is thus carried away. 



476. This whole amount of cutaneous exhalations, sensi- 

 ble and insensible, will average about the same in a healthy 

 individual, from/ day to day or from month to month. 

 Yet there are many circumstances that cause it to vary. 

 Climate and season influence it ; it is more in summer than 

 in winter; philosophers estimate it to be forty ounces in the 

 south, and twenty ounces a day in the north of Europe. 

 Active exercise running, hard labor will increase it, 

 and make the sweat visible, so as to run abundantly in drops. 

 Unusual quantities of clothing prevent the radiation of heat, 

 and cause it to accumulate ; the skin then becomes warmer, 

 until an increase of perspiration occurs and relieves by its 

 evaporation. 



Smith's Philosophy of Health, Vol. II. pp 391, 393. 



