KESPIKATOKY SENSE. 4:79 



As expressing nearly all that is known, even at the pres- 

 ent day, regarding the mode of formation of carbonic acid 

 in the economy, we may take the following concluding passage 

 from the paper of Collard de Martigny, published in 1830 : * 



" The carbonic acid expired is a product of assimilative 

 decomposition, secreted in the capillaries and excreted by the 

 lungs." 



The carbonic acid thus produced is taken up by the 

 blood, part of it in a free state in solution, particularly in 

 the plasma, and a part which has united with the carbonates 

 to form bicarbonates. Carried thus to the lungs, the free 

 gas is removed by simple displacement, and that which 

 exists in combination is set free by the acids found in the 

 pulmonary substance. 



3. What is the nature of the intermediate processes, from 

 the disappearance of oxygen to the evolution of carbonic 

 acid? A definite answer to this question would complete 

 our knowledge of the respiratory process ; but this, in the 

 present state of the science, we are not prepared to give. We 

 can only repeat what has already been so frequently referred 

 to, that oxygen must be considered as a nutritive principle, 

 and carbonic acid a product of excretion. The intermediate 

 processes belong to the general function of nutrition, with 

 the intimate nature of which we are unacquainted. We 

 have not sufficient evidence for supposing that this process 

 is identical with what is generally known as combustion. 



The Respiratory Sense; or Want on the part of the System 

 which induces the Respiratory Movements. \Besoin de 

 Respirer.} 



We are all familiar with the peculiar and distressing 



1 Loc. cit., p. 160. The author adds: "The chemical theory of Lavoisier, 

 of respiration, is a gratuitous supposition. This function should be considered 

 as a complete series of acts of general assimilation." 



