HEART. 
ra and t} ney are feen it In be — columns as the ey Cc 
_to this vifcus. Imagine es each of thetwo circul 
trees united by their ‘trunks ks, and fending oe Beant the 
one into the lungs, the other into all p e body. 
Each of the two fides of the heart is amuses she fe two 
trunks, which it ferves to unite tozether ‘fo as to form one 
general canal, according to the de {eriptio: 1 already given. 
Authors igs generally re prefented the arterics and veins 
as forming cach, by the whole of its ran uifications, a general 
cone, of whi o the bafis.is in all parts of the body, aad the 
apex at the heart. of confidering the. fubject is 
authorifed by the fact that the fum of the branches exceeds 
in diameter the trunks from which they arife: in this point 
"of view, each half of the heart is placed at the apices of two 
ce which would, but for its intervention, be united to- 
eae to all parts of the body) is diltinguifhed by its wide 
expanfion. 
Placed Seas thefe two cones, each fide of the heart 
tault be regarded as an agent of impulfion, driving the blood 
in one cafe towards all pects of the body, in the other to- 
wardsthe lungs. If the two eoxres-of each circulation com- 
municated together by: fas apiece the fides of the v ere 
comp m would be manifeftl a ect to kee 
the eugete from et bafe eh one et that of the Seg at 
is, illary fyftem, 
~ and cirri f eae oy of the lung to that of the bod 
at large. The cotrfe is obviouily too long, and the vital 
powers of the veffels too weak ; hence-the neceffity of the 
heart. This confequence Si es = vg another arra: 
nae whe we proce ced to explain, 
3 eart tot he ie p eepeery ae yftem, than is tra- 
verfed by the black bload, ir om. the heart to the 
pulmonary capillaries, tre Sem x. of Sew organ, whi O- 
Is the fluid in the former cafe, muft pala ack greater 1 
power than is required for the purpofe of kee ping aE motion 
an the latter inilance. Nature has fulfilled this objet, by 
snes g the ventricle of the r 
es cog = of the ood’ 8 aaa a that if it a 
ir trunks. at the finus of vena portarum 
which occupies the pofition of the heart in the oe fyftem of 
i ick blood, and in that of red blood. It is therefore poffi- 
gee 
a 
teries, and confequently draw their 
b 
e ae sof black blood d may be 
oo 
ble fo 0 conceive, if, how the he art may y be Aeficient, phe 
and eae ci can 5 banaly accelerate ‘the current of this fluid; 
3dly, how, after the pulfations of the heart have been en- — 
tirely fufpended in fyncope, afphyxia, &c. an ofcillatory move- 
ment {till remains, a real progreffion of the blood from one 
capillary fyftem to the other, fince pete bud will till flow in 
fome degree from an opened artery ‘in. ‘This motion is in 
truth very feeble, and cannot lait iene: ; but wie is may eX- 
iit, without the eee of the heart, is proved by the fact 
of the black bloo eing conveyed, without af dina “hi 
impultion, from b he inteflines o the liver ; and hence we in- 
TOVE, - 
fer, that the ceflation of the heari’s ation does not 
as fome authors have Sectors: that the bloed no longer 
moves; 4thly, we know that in feveral animals of the lower 
claifes eve? 18 eo heart, although difting& veflels and circ 
lating fluids ex 
ineral U, ries 7 the red- ey | Ciscoe, —This furnifhes 
the materials of all the fec except the bile. From 
this fource alfo the hobo ig to the ferous, oan 
e fluids 
veffels, which convey the means of nutriti 
the various organs of the body,are continsies with the ar- 
fluids from the red 
lood. Even in thofe partte to which black blood is fent, 
as the lungs and the liver, there are veflels containing. red 
blood; manifettly deftined to fulfil the seh of nutrition. 
The red blood communicates to all parts that ihe agi- 
tation or concuffion (fécouffe) fo neceffary to t 
ance of their funétions, and fo clearly recognizable in the 
rain. Thus the. red blooded circulation is the moft import- 
ant, and peas concerned i in the principal phenomena 
of the living econom 
General Ufes of the yee ogee ioe, —The circuls- 
tion of black blood, on the 
be defigne ed. eet to. make soe d the 
in 
d hiel had: { lour have ae 
an which ha given it a crimfon ea cs 
HE 
earryi fee in the ly 
ferous 
geftive functions, is Fecu 
canal, and circulates there. * eo : 
yerfe the 28 in the aét of refpirationy are min 
the blood in 
stage the firlt place 
be expelled from the body, an 
In the latter r point of view € ee 
m to another, although the heart, difeafed 
rary, foreign to all the 
