CONSTANTS 565 



there would be produced about the same volume (or rather 

 less) of carbonic acid, which would contain about 225 

 grammes (8 ounces) of carbon. During the same time 

 about 250 grammes (half a pint or 9 ounces) of water 

 would be given off from the respiratory organs. 



In 24 hours such a body would vitiate 1,750 cubic feet 

 (1 cubic foot = 28 3 litres) of pure air to the extent of 1 per 

 cent., or 17,500 cubic feet of pure air to the extent of 1 

 per 1,000. Taking the amount of carbonic acid in the 

 atmosphere at 3 parts, and in expired air at 470 parts in 

 10,000, such a body would require a supply per diem of 

 more than 23,000 cubic feet of ordinary air, in order that 

 the surrounding atmosphere might not contain more than 

 1 per 1,000 of carbonic acid (when air is vitiated from 

 animal sources with carbonic acid to more than 1 per 

 1,000, the concomitant impurities become appreciable to 

 the nose). But for health, the percentage of carbonic 

 acid should be kept down to half this amount or '5 per 

 1000, so that the body should be supplied with at least 

 about 50,000 cubic feet of fresh air each day. A man of 

 the weight mentioned (11 stone) ought, therefore, to have 

 at least 1,000 cubic feet of well-ventilated space. 



V. Cutaneous Excretion. 



Such a body would throw off by the skin — of water 

 about 650 grammes (23 ounces or 1 pint) ; of solid matters 

 about 20 grammes (300 grains) ; of carbonic acid about 

 25 grammes (400 grains) in 24 hours. 



VI. Renal Excretion. 



Such a body would pass by the kidneys — of water about 

 1,500 grammes or cubic centimeters (53 ounces or 2h 

 pints) ; of urea about 33 grammes (500 grains or IJ oz.), 

 and about the same quantity of other solid matters in 24 

 hours. 



