TEDE AASRAY, 
into the capillary fyftem. 
In fhort, it. is contraGion from 
the ceflation of extenfion. ; ‘ 
ble of exciting the heart’s motion in various ways. 3dly. 
$ many variations in 
very flight fympathetic 
rgans. For the {ame reafons, ot 
parts have very little Tpaineeaie influence on this fyftem. 
fympathetic variations of the pulfe have 
us form 
immediate communications between them. ‘The bloodis all 
of one kind in the foetus. Bichat afcertained this fa& by 
examining guinea pigs while {till in’ the uterus: all their 
veffels contained venous blood, at leaft as far as co 
t It, on the regnant bitch. 
always found the blood of the umbilical veffels to prefent the 
ch have been deftroyed by af} phyxia. 
it does 
Le ay : x to the adult. 
i i, the capillaries of the abdomen 
ss the placenta: its common trunks are the inferior 
of twe fyitems, very different ; 
The firft bas its ; 
, of the lower. limbs, - 
' arrangement, to that - 
which is feen after refpiration has begun : the defeription ' 
of the umbilical veffels, and the canalis arteriofus, will be 
found under Emgry 
Bichat conceives, that thofe peculiarities which diftinguifh 
the foetal circulation, do not undergo a fudden revolution at 
the time of birth, but that there is a gradual change towards 
ructure of the circulating organs, as they are found in 
an individual which has breathed before birth, « T 
portions of blood are almoft completel 
firft months of feetal exiftence : all that which comes through 
the inferior vena cava is fent into the afcending aorta, while 
endi ; 
e foramen ovale, and the d riofus, are y 
contra¢ted before birth, and the circulation approaches ta- 
wards the ftate in which it is found after refpiration has 
commenced. The introduction of red blood into the eco- 
birth. We fhould form an erroneous conception of the 
fubjeCt, if we fuppofed a fudden change at birth. Exami- 
nations of the foramen ovale, and canalis arteriofus, at dif- 
ferent periods of pregnancy, will fhew us that they cont 
Bie” ta 3 fo that if the child remained beyond its natu- 
term in the uterus, and the fame procefles were continu 
the blood would at laft circulate as it does in the adult, 
merely from the pulmonary to the general capillary fyftem, 
But it would be of one uniform colour. I 
conitant relation between quantity of blood fent by the 
right ventricle to the lunge, and that which the left. propels 
into the lower parts of the body, As the former increafes, 
returns to the left ventricle ; 
arterial tiffue is more pliant in the foetus than in, the 
