230 THE VITAL FUNCTIONS. 



almost constantly find that a circulatory motion 

 of the nutrient fluids is established ; and the 

 function which conducts and regulates their 

 movements is emphatically denominated the Civ' 

 culation. Several objects of great importance 

 are answered by this function ; for, in the first 

 place, it is through the circulation that every 

 organ is supplied with the nutritive particles 

 necessary for its developement, its growth, and 

 its maintenance in a healthy condition ; and 

 that the glands, in particular, as well as the other 

 secreting organs, are furnished with the materials 

 they require for the elaboration of the products, 

 which it is their peculiar office to prepare. A 

 second essential object of the circulation, is to 

 transmit the nutritive juices to certain organs, 

 where they are to be subjected to the salutary in- 

 fluence of the oxygen of the atmosphere ; a pro- 

 cess, which in all warm-blooded animals, com- 

 bined with the rapid and extensive distribution 

 of the blood, difliises and maintains throughout 

 the system the high temperature required by the 

 greater energy of their functions. Hence it 

 necessarily follows that the particular mode in 

 w hich the circulation is conducted in each re- 

 spective tribe of animals, must influence every 

 other function of their economy, and must, there- 

 fore, constitute an essential element in deter- 

 mining their physiological condition. We find, 

 accordingly, that among the characters on 



