CONSUMPTION OF OXYGEN 119 



kilograms) to the height of 656 feet (200 meters), consumes 3874 cubic 

 inches (63.48 liters) of oxygen per hour. 



" 5. The same man, during digestion, accomplishing the labor neces- 

 sary to raise, in fifteen minutes, a weight of about 16 pounds 3 ounces 

 (7.343 kilograms) to the height of 692 feet (21 1.146 meters), consumes 

 5568 cubic inches (91.24 liters) of oxygen per hour." 



Immediately after birth the consumption of oxygen in warm-blooded 

 animals is relatively very slight. It has been shown that just after birth, 

 dogs and other animals will live for half an hour or longer under water ; 

 and cases are on record in which life has been restored in newborn chil- 

 dren after seven, and, it has been stated, after twenty-three, hours of 

 asphyxia (Milne-Edwards). During the first periods of extra-uterine life, 

 the condition of the newly born is nearly that of a cold-blooded animal. 

 The lungs are relatively small, and it is some time before they fully 

 assume their office. There is, also, very little power of resistance to a 

 low temperature. Although accurate researches regarding the compara- 

 tive quantities of oxygen in the venous and arterial blood of the foetus 

 are wanting, it has frequently been observed that the difference in color 

 is not so marked as it is after pulmonary respiration has become estab- 

 lished. The direct researches of W. F. Edwards have shown that the 

 absolute consumption of oxygen by very young animals is quite small ; 

 and the observations of Legallois, on rabbits, made every five days dur- 

 ing the first month of life, show a rapidly increasing demand for oxygen. 



The consumption of oxygen is greater in lean than in fat animals, 

 provided they are in perfect health. The consumption is greater, also, 

 in carnivorous than in herbivorous animals ; and in animals of different 

 sizes, it is relatively greater in those which are very small. In small 

 birds, such as the sparrow, the relative quantity of oxygen absorbed was 

 ten times greater than in the fowl. 



During sleep the quantity of oxygen consumed is considerably dimin- 

 ished ; and in hibernation it is so small, that Spallanzani could not detect 

 any difference in the composition of the air in which a marmot in a 

 state of torpor had remained for three hours. In experiments on a mar- 

 mot in hibernation, Regnault and Reiset observed a reduction in the 

 oxygen consumed to about one-thirtieth of the ordinary quantity. 



It has been shown by experiments that the consumption of oxygen 

 bears a nearly constant ratio to the production of carbon dioxide ; and 

 as observations on the influence of sex, the number of respiratory acts 

 etc., on the activity of the respiratory processes have been made chiefly 

 with reference to the carbon dioxide exhaled, these influences will be 

 considered in connection with the products of respiration. 



Experiments on the effect of increasing the proportion of oxygen in 



