PRESStfRE OF AIK. 



ask any one, whether he would venture to assert 

 that he believes this to be the way in which the 

 lungs acquired the faculty of decomposing atmos- 

 pheric air; and that he believes that this hypothesis 

 is sufficient to account for the composition of this 

 air, which so exactly suits the operation of these 

 lungs, and which contains that exact portion of 

 caloric which the animal ceconomy requires ! It 

 is worthy of remark, that cold-blooded animals, 

 which are not furnished with this breathing ap- 

 paratus, are so constituted that their temperature 

 changes with every change of the temperature of 

 the surrounding medium. Frogs have been abso- 

 lutely frozen so as to chip like ice, and then when 

 carefully and gradually thawed, have been com- 

 pletely re-animated. 



Lastly, it may be remarked, that the interval 

 which there is between every inspiration seems to 

 have been designed to allow time for the nitrogen 

 gas which is throwirout of the lungs to mount in 

 the air above the head, in order that a fresh por- 

 tion of air might be taken in, and that the same 

 air might not be repeatedly breathed. 



During that remarkable interval that always 

 occurs in breathing, there is sufficient time al- 

 lowed for the noxious fluids to separate; the first 

 to ascend, while the other preponderates, leaving 

 a. space for a fresh current of uncontaminated 

 atmospheric air. Thus every thing is prepared by 

 Divine Goodness, without any care or forethought 

 ,of purs, for a new inspiration. 



" The 



