OF THE ARTERIES GENERALLY. 119 



to act as a stimulus to increase their size, and to disease the 

 synovial secretion within. 



SECTION XI. 



OF THE VESSELS ; OR OF ARTERIES, VEINS, AND ABSORBENTS. 



DESCRIPTION OF PLATE IV. 



THE ABDOMEN, DEPRIVED OF THE INTESTINES. 



A, The posterior aorta, near its termination ; B, the posterior 

 cava ; C, C, the ureters ; £>, D, the kidneys ; E, the renal 

 artery ; F, the renal vein ; G, the stomach ; H, the duo- 

 denum tied ; /, the splenic artery ; J, the liver ; K, the ante- 

 rior mesenteric artery. 



OF THE ARTERIES GENERALLY. 



The arteries are canals originating from the ventricles of 

 the heart by two trunks, the aorta and the pulmonic ; 

 whose subdivisions are destined to supply the whole body 

 with blood. Considered generally, arteries are long tubes ; 

 which by reason of their numerous bifurcations become 

 smaller as they proceed to the extreme parts. However, 

 the extremities of the arteries, though so much smaller 

 than the original trunk, nevertheless, if put all together, 

 w^ould contain ten times as much as the parent vessels. In 

 their course an especial regard is observed towards their 

 safety ; hence they are mostly deep seated ; and invariably 

 pass on the inner sides of the limbs, or on the side that is 

 flexed. They appear equally guarded against accidental 

 pressure or tension, by passing over the bending surface of 

 a joint ; and where they are situated in soft parts, liable to 

 extension, as in the tongue, the arteries pursue a serpentine 

 or very crooked course. Their being thus convoluted, 

 however, answers another end than saving them from being 

 stretched ; as the arteries, before entering the brain and the 

 testicles, are to be seen winding about in various directions ; 

 the intention of which construction is to prevent the blood 

 from being urged too violently upon such important organs. 

 All arteries are composed of three different coats or cover- 



