40 BOTANIC PHYSICIAN. 
OF THE ARTERIES. 
Arteries are elastic membranous canals, which pulsate; they ale 
ways become narrow as they proceed from the heart towards the ex 
~ tremities. They originate from the two ventricles of the heart, viz 
the lung artery, from the right, and the fountain artery (aorta) from 
the left ventricle ; so that there are only twoarteries, of which all the 
rest are branches. The arteries terminate in veins, exhaling vessels, 
or they unite with one another. They are composed of three mem 
branes called coats: an external one, a middle coat, which is mustue 
lar, and an inner, which is smooth. Their use is to convey the 
blood from the heart to the different parts of the body, for nutrition; 
preservation of life ; generation of heat; and the secretion of dit 
<i ne co - = we 
oe . 
~ 
THE FOUNTAIN. 
_ the abdomen, in which it proceeds by the left side of the spine, to 
the last loin vertebre, where it divides into the two flank arteries. a 
In this course it gives off, just above its origin, two crowning arte 
_ ¥ies to the heart, and then forms an arch. 
_ ~The arcn of the fountain gives off three branches, which supply 
the head, neck, and arms with blood; these are, 
The rirst prancu, which divides into the right head, and 
right chest arteries, ag 
the neck, one on each side of the windpipe, to the angle of the lower 
__ ‘Phe ExTernat weap gives off ¢; s 
face: 1. Shield-a 7 eight branches to the neck and 
the tongue. 
, 
Of the brai 
7 femporal arteries, which 
