153 



carbonic acid produced at 26.6, a difference in vo- 

 lume equal to ~ 2 * : and Dr Bostock concludes, 

 that in 24 hours, a man consumes somewhat more 

 than 26 cubic feet of oxygen gas, and produces 

 about 22 cubic feet of carbonic acidf, so that the. 

 bulk of the acid falls short of that of the oxygen 

 eras by ~ of the whole. It follows from all the 



fc> J 6.3 



foregoing facts, that the volume of carbonic acid, 

 produced by the respiration of animals, is, in all 

 cases, from one-fifth to ~ less than that of the 



f D.5 



oxygen gas which has disappeared during that pro- 

 cess. 



123. From what cause then does this loss of bulk 

 proceed ? It cannot arise from an absorption or at- 

 traction of the oxygen gas, and subsequent combi- 

 nation of it with the blood ; for both of these cir- 

 cumstances are forbidden by the actual structure of 

 the lungs. But we have seen, that, by the conver- 

 sion of oxygen gas into carbonic acid, in the process 

 of combustion, a diminution of its bulk (11.)? a - 

 mounting nearly to one-seventh, takes place : and 

 we have traced this diminution, in a less degree, 

 when the same change is produced on oxygen gas 

 by the growth of seeds and of plants, by the respi- 

 ration of the inferior animals, and also by its being 

 placed in contact with blood. It is true, that the 

 degree of this diminution varies, in these several 

 examples, from ^- 7 to -- of the volume of oxygen 



* Researches, p. 434-. 



f Essay on Respiration, p. 99- 



