28 RESPIRATION TENDS TO 



may, by entering into combination with the oxygen 

 of the air, protect the system from its influence, then, 

 the substance of the organs themselves, the fat of 

 the body, the substance of the muscles, the nerves, 

 and the brain, are unavoidably consumed.* 



The true cause of death in these cases is the respi- 

 ratory process, that is, the action of the atmosphere. 



A deficiency of food, and a want of power to con- 

 vert the food into a part of the organism, are both, 

 equally, a want of resistance ; and this is the nega- 

 tive cause of the cessation of the vital process. The 

 flame is extinguished, because the oil is consumed ; 

 and it is the oxygen of the air which has consumed it. 



In many diseases substances are produced which 

 are incapable of assimilation. By the mere depriva- 

 tion of food, these substances are removed from the 

 body without leaving a trace behind ; their elements 

 have entered into combination with the oxygen of 

 the air. 



From the first moment that the function of the 

 lungs or of the skin is interrupted or disturbed, 

 compounds, rich in carbon, appear in the urine, 

 which acquires a brown colour. Over the whole 

 surface of the body oxygen is absorbed, and combines 

 with all the substances which offer no resistance to 

 it. In those parts of the body where the access of 



* For an account of what really takes place in this process, I 

 refer to the considerations on the means by which the change of 

 matter is effected in the body of the carnivora, which will be found 

 further on. 



