SECOND TREATISE 



ON RESPIRATION 



The lungs are placed in a recess so sacred and hidden 

 that nature would seem to have specially withdrawn 

 this part both from the eyes and from the intellect ; 

 for, beyond the wish, it has not as yet been granted 

 to any one to fit a window to the breast and redeem 

 from darkness the profounder secrets of nature. For 

 of all the parts of the body, the lungs alone, as if 

 shrinking from observation, cease from their move- 

 ment and collapse at once on the first entrance of 

 light and self-revelation. Hence such an ignorance of 

 Respiration and a sort of holy wonder. Still, let me 

 draw near to the inmost vitals, and, concerning so 

 obscure a matter, make at least a guess. 



In discussing on Respiration I shall follow the 

 method pointed out by nature and begin therefore 

 with inspiration. 



Every one knows that when we inspire, air rushes 

 into the expanded chest and inflates the lungs. But 

 authorities are not equally agreed as to the cause of 

 the air rushing in with such vehemence. Some 

 account for it by a vacuum and an attraction of I 

 know not what imaginary sort. 



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