V] THE RESPIRATORY ORGANS 73 



In the case of rarbohydrate 1 vol. of produces 1 vol. of CO.. 

 In tlie case of protein 1 vol. of O produces -83 of CO;. 

 In tlio case of fat 1 vol. of O produces -71 of CO2. 



The ratio _ ^ :r is called the resi^iratory quotient. 



O2 consumed 



This in a man on an ordinary mixed diet is -9 or somewhat less. 

 It can l)e raised by increasing the relative amount of carbo- 

 hydrate in the food, and lowered l)y ])rotem or by fat. Thus 

 the respiratory quotient is higher in her})ivorous animals than 

 in carnivorous ones. If a herbivorous animal be kept on carbo- 

 hydrate diet its respiratory quotient maj^ be raised to unity, but 

 only for a short time, since it very soon begins to consume its 

 own stored up proteins and fats. 



