53 



of the power living with so deficient a respiration, is the diminu- 

 tion of temperature. The same thing occurs in the last hour of 

 life in many cases of diseases, and particularly those of the 

 brain, of the respiratory organs, and in that dreadful disease of 

 children called scleroma. 



It is easy to understand how a considerable breathing becomes 

 less and less necessary when the temperature of the animals 

 under experiment is diminishing. 



Whatever may be the function of oxygen, it is positive that 

 most of the chemical changes which take place in the living ani- 

 mals are accompanied with a consumption of oxygen. If so, 

 when these chemical changes are diminished, the consumption of 

 oxygen ought to diminish. Now, as every diminution of the 

 temperature of an animal produces a proportionate diminution in 

 nearly all the acts of organic and animal life, and as these acts 

 are all accompanied by chemical changes in which oxygen is 

 consumed, it follows that, when they diminish, the consumption of 

 oxygen also diminishes. 



In the act of running, or in a rapid walk, we consume much 

 more oxygen than in a state of rest. What we call rest is merely 

 a state of diminished activity; and when the temperature of a 

 mammal has been cooled down, the activity of most of the func- 

 tions is much more diminished than in the most complete rest. It 

 results from this fact, that when a warm blooded animal has lost a 

 notable part of its ordinary warmth, its consumption of oxygen 

 is much less than in a state of rest. 



If the ligature of the trachea is made simultaneously on two 

 adult mammals of the same species, one of them being at its nor- 

 mal temperature, and the other at a temperature of 5 Cent. 

 (9 Fahr.) lower, we observe that this last one lives six, seven or 

 eight minutes, and the other from one and a half to three 

 minutes. If we suppose the quantity of oxygen existing in the 

 lungs and in the blood of these two animals is precisely alike in 

 both ; and if we admit that death occurs in asphyxia, either from 

 want of oxygen or by an action of carbonic acid, in both cases 

 these two animals ought to live a different length of time, because 

 the consumption of oxygen contained in blood and the produc- 

 tion of carbonic acid are quicker in one of them than in the 

 other. This explanation is so true, that when movements are 



