ON THE FUNCTfONS OF THE HEART AND ARTERIES. f^J 



example, animal bodies are incapable of beinsj frozen by a 



considerable degree of cold, because animals have the power 



of generating heat; but the skin of an animal has no power 



of generating an acid, or an alkali, to neutralize the action 



of an alkaline or an acid caustic, and therefore its tpxture 



is destroyed by the chemical attraction of such an agent, 



when it comes into contact with it. As far, therefore, as the As far as the 



functions of animal life depend on the locomotions of the p^nd' 'on mo-' 



solids or fluids, those functions must be capable of being tion they obey 

 illustrated by the consideration of the mechanical laws of j"'^^^^''"'^^^ 

 moving bodies; these laws beii?g fully adequate to the ex- 

 planation of the connection between the motive powers, 

 .which are employed in the system, and the immediate ef- 

 fects, which they are capable of producing, in the soiids or 

 fluids of the body: and it is obvious, that the inquiry, in 

 what manner, and in what degree, the circulation of the the circulation 



blood depends on the muscular and elastic powers of the thf f^frtre an 

 ^ . ^ object of hj- 



heart and of the arteries, supposing tiie nature of these drauUts. 



powers to be known, must become simply a question be- 

 longing to the most refined departments of the theory of 

 hydraulics. 



In examining the functions of the heart and arteries, I Inquiries into 

 shall i'.jquire, in the first place, upon the ground of the hy- \'^jhe"}^earT 

 drauiic investigations which I have already submitted to tlie and arteries. 

 Royal Society*, what would be the nature of the circula- 

 tion of the blood, if the whole of the veins and arteries 

 were invariable in their dimensions, like tubes of glass or of 

 bone; in the second place, in what manner the pulse would 

 be transmitted from the heart througla the arteries, if they 

 were merely elastic tubes; and in the third place, what 

 actions we can with propriety attribute to the muscular 

 coats of the arteries themselves. I shall lastly add some 

 observations on the disturbances of these motions, which 

 may be supposed to occur in difif'erent kinds of inllanima- 

 tions and fevers. 



» See Jourca], vol. XXII, p. 104. The reader is requested to sub- 

 stitute ia p. 121, 1.5 from hot., forzn V —t m V—-> in p. 323,1. 



8 and 9 from bot., for wben c ed, whence dj and ia p. 12^2; at the end 

 of 1. 6 from hot., to add—is denoted hy a v, 



WheQ 



