HEAR T. 
Accidental Developement of the Syftem.—The formation of their fides, ap rato! ryt the arteries, are thin, the 
mew arteries feems to take place in fome circumftances; as in may often be di inguithed through the in ts by kw 
the cafe of adhefions in the cheft or abdomen, &c. ; but there , inences, which they » have a pale 
las been no minute inveftigation of this fact. Thefe veffels blue tint, made up of the dark purple of the venous blood, 
are dilated, when any obitruction is formed to the paflage of and the whitenefs of the fkin, and more diftiné in P . 
the blood by the ordinary channels ; as when the artery of a tion as the fin is thin and clear. No part of this caléor 
limb has been tied in the operation for an aneurifm, or when _refides in the veflels themfelves. 
a {welling of this kind has undergone a {pontaneous cure. In the interior of the body tho veins almof univerfally 
A fimilar dilatation generally takes place when tumours are accompany the arteries, rally a common” cellular 
formed, particularly fuch as are attended with acute pain. {pace contains both the trunks of the two kinds of vellels 
In amputating a thigh, for difeafed knee-joint, the arterics and the nerves. ‘The azygos is, however, an inf vein. 
i if the difeafed part ‘The doepfeated veins are more capacious than the arterica, 
be at the time ina ftate of aétive inflammation, and ufually more numerous, as in the limbs, where each 
Vafeular Syflem containing black Blood —'The red blood cir- artery has two correfponding venous veffels. 
Ww proportions 
The veins originate in the general capillary fyftem, and ‘The latter author Cte 191 and 100 as the 
which one The veins do 
arteries. leon organs veins pafs out in the fame fitua- merely, but alfo in number ; and the proportion of the former 
“ , ‘Miger rae 
arteries enter ; are ome. The united 
ceptions to this rule. ‘The arteries of the brain enter below, areas of all the veins will, therefore, far furpafs thofe of the 
the voins go out above; the at the arteries, if the former veficls are not only more capacious 
lower part of the liver, and the latter efcape behind. Thefe individually, bat alfo more numerous, Large venous plex- 
aferences have no onthe circulation. Befides the veins, ules exift in many parts without any corref; | 
he arteries, there is an order of thefe as under the fkin of the extremities and neck, in the fper- 
velfels which have a diltin€t courfe. ‘The organs near the matic chord, about the bladder and ive organs, ke. 
i i calculations Bichat the uncertainty to 
If the veficl thould 
ftem, are much t 
veins which enter it. Here the difpro- from |! t bene we may give to them what 
between the two fyftems begins. capacity we pleafe, acoording to the mode in which we deflroy 
the veins, after commencement, is the animal, veins vary equally in fixe in the living fabje4, 
the limbs and exterior parts of the trunk rs ine Sen yet ape full: hence thofe under the 
claffes ; an interior, fellowing the courfe of thin are une and at others hardly difting with. 
which is fabcutancous. A able. Whenever the mafs of blood is diminished, from what. 
i in ever weIn: 
fuperficial deepfeated veins in the riety, on account of their more firm texture, change in a much 
ve ks which {maller degree. When there is fuch tothe 
3 3 i # 
oe ey Fe i 
ie former, 
body exhibits a remark- thao in the latter. A fimilar obfervation be made con. 
‘contain Black blood over cerning the two fides of the heart the Fight ne _eape. 
ood. In this fituation ap cious | ; more blood. If this 
