¥ AND FAMILY DISPENSATIORY oy 
stances; as two, three, four, or five, fingers, between,each, according to the lengta 
oof the vefiel..; As to their magnitude, they.are greater whece the plenty and recgurle 
»of. the blood is. moft vehement, being in formlike the nail on a man’s finger or the 
~ horned, moon, as the figma-fhaped valvesof the heatt ;. and. in. their fubftance ex- _ 
‘ceeding thin, but.very compact, leit. they fhould break, by a. ftrong intercourte of 
othe blood.|. The.ufes of the valves are, 1. To ftrengthen the.veins, whereas the 
arteries are otherwife made ftrong by the double coats, 2. To ftop the too violent 
«motion.of the blood, left.it fhould move violently out,of the great veins into the. 
little ones, and tear them. 3. To hinder the blood, from regurgitating,.or going: 
backwards... Hence the caufe of a varix is. apparent, becaufe thick heavy blood. 
. long. retained againft the valves makes a dilatation , for without the valves the. veins 
» would {welluniformly and all of an equal bignefs, and not in the manner of. varices. 
The chief veins of the whole body are of three kinds, fict, theveaa cava: Secondly 
baht porta: thirdly, vene JaGee: from which feveral other eminent.veins arile, 
ohaving particular denominations. The vena cava.or magna is. fo called. becaufe or 
pits largenefs, being the greatett in the whole body, and the original of all other veins 
-whieh-do. not proceed fromthe vena porta. It takes its beginning from the liver, 
» where, having fpread many veins through the upper parts thereof, they are aboutthe 
-gop collected into one trunk, which is prefently dividedinto two parts, viz, the. upper 
or afcendant trunk, and the lower ordefcending trunk. 
The afcending trunk of thevena cava, which is the greater, perinesirs i diaphrag- 
<a or midriff, and. is {pread through the breaft, neck, head, and arms. Iti is carried 
-undivided as far.as the jugulum,. and has four branches; viz. 1. Phrenica,, vena dis- 
opbragmatica, the: midriff veins,.on cach fide one, which fend their branches to. the 
> pericardium and diapbragma. 2. The vena coronaria, which i is fometimes double, encom- 
> paffing the bafis of che heart, at whole rife alittle valve is placed, to. hinder the bload 
returning to the trunk ;, and with a continued paffage it isjoined to. the artery, thar 
~dt may. therefrom receive the blood, which is to return to the cava: 3, Azygos fai 
- pari, the folitary vein, fends chief intercoftal branches to. the eight lower.ribs: arifing 
about the fifth vertebre of the breaft, from the hinder part of the veya cavum, then, 
_ about.the flefhy appendices of the diaphragma, it enters the cavity of the. abdanes, 
. where.on the left fide it is: inferted: praca vein; on the right fide -into,the 
trunk,of thecava, 4. Sudclavi ches of the cava by the.channel bones, are 
adiciichiornem only. branes oon fieach de 5. each. of which. is; divided. inso 
-¢ avit-and axillaris. From the fubclavis come forth two 
Fyn me pr cin and mufcles of the Minder, part ofchesneski: 
ee _— of the neck; and they arecither external or 
internal, 
