272 EFFECT OF FUR AND CLOTHES 



Laulanie). The food-stuffs vary in this respect, the effectiveness 

 of proteid, carbohydrate, and fat being as 20 : 10 : 7. When the 

 external temperature is high even a moderate increase in diet raises 

 the heat production, and the body temperature must then be 

 regulated by a corresponding increase in the water output. 



Thus in guinea-pigs while at C. the consumption of food did 

 not materially affect the total metabolism, at 30 C. it increased it 

 by 39 per cent. At 30 C. the water output of a fasting dog was 

 increased 2 per cent, by feeding 100 grm. meat, 39 per cent, by 

 200 grm., and 104 per cent, by 302 grm. On the other hand, such 

 a diet had little effect on the dog at 20 or 7 C. 



.Rubner calculates that the heat lost by evaporation by a 

 moderately stout man on a hot day while out of doors may be at 

 the rate of 3200 Calories per diem. At 37 C. Wolpert observed 

 a loss of 441 grm. of sweat per hr. during rest, and 535 grm. 

 during work, or 3 1. in six hrs. a great loss for a man with 

 6-7 1. of blood in his body. 



A fat man observed by Wolpert at 37 and 34 per cent, rela- 

 tive dryness of atmosphere could not perform a slight amount of 

 work without rise of body temperature. 30 C. seems to be the 

 limit of heat which fat people can easily endure. 



These results show how the danger of heat-stroke is increased by 

 overfeeding in very hot moist days. Under conditions of high 

 temperature and great humidity, the production of heat on the 

 ordinary maintenance ration may be so great as to produce patho- 

 logical effects, and the consumption of food is then instinctively 

 reduced below the maintenance requirement, with consequent loss 

 of body weight. 



A naked man exposed to wind (8 m. per sec.) used 52 grm. 2 

 per hr. against 27 grm. when clothed. The effect of the wind was 

 greater than that of a cold bath (Wolpert). 



THE EFFECT OF FUR AND CLOTHES 



A fasting dog after shaving stood 30 C. without any noteworthy 

 increase of water output, for lessened heat production aided by radia- 

 tion and conduction sufficed. The temperature at which increased 

 sweating came into play was by this means raised 10. In certain 

 of the workings of Cornish mines the temperature may reach 93 F. 

 owing to the oxidative processes which occur in the soil. The air is 

 also saturated with moisture. The men can work at 80 F., but 



