Chap. 29.] Circulation of the Blood. 305 



The motion of the fluids of the valvular lymphatic 

 fyftem is quite diflincl: from the circulation of the blood. 

 Thefe veflels begin by open mouths, which perform 

 the office of abforptioni and their contents are not de- 

 rived, like thofe of the red veins, from the extremities 

 of arteries ; their fluids are therefore propelled, with- 

 out any aid from the heart, by their own contractile 

 powers. 



The moft remarkable functions, to which the circu- 

 lation of the blood is fubfervient, are fecretion, the 

 nourifhment of the body, and certain changes which 

 the blood undergoes in its pafifage through the lungs j 

 6f thefe it will be proper to treat in the chapters im- 

 mediately fucceeding. 



- VQL. III. 



