64 THE LAWS OF ORGANIC 



while a much greater quantity of air at all 

 times exists in the lungs ; and from this it is to 

 be inferred, that the successive chemical changes 

 are slow, and of a delicate description. If we 

 send in a quantity of air greater than what is 

 consistent with the laws which nature has esta- 

 blished, we destroy the concord connecting the 

 various agents ; and this abundance, instead of 

 promoting the different decompositions, tends to 

 destroy the conditions on which these depend. 



LI I. During the process of inflation, the heart 

 continues to beat ; but this is no proof that the 

 circulation is in its normal state, or that the 

 lungs perform their usual office ; for these phe- 

 nomena occur in the human subject when the 

 temperature of the system has fallen consider- 

 ably. In fine, the heart occasionally palpitates 

 when the lungs are oppressed with blood ; and 

 this symptom is regarded as an increased action 

 of the organ, yet it is often accompanied by a 

 diminution of temperature. It is therefore evi- 

 dent, that the contractions of the heart are far 

 from being criteria of proper chemical changes 

 operating on the lungs. 



LI II. The colour of the blood is often addu- 

 ced as showing that the venous is converted into 

 arterial as in health ; but this change of colour 

 takes place in those cases it} which respiration is 

 deranged and the temperature diminished. 



