404 



the aorta, immediately below the origin of the left subclavian arterr. The 

 aorta, at its origin, is therefore filled with arterial blood, sent towards 

 the upper parts of the body, by the contraction of the left ventricle, while 

 the remainder of this artery contains venous blood, which is expelled by 

 the combined action of both ventricles. 



It is impossible, in this arrangement, not to recognize an evident design. 

 In fact, if the whole force of the heart had been exerted to send the blood 

 towards the brain, the delicate texture of this viscus would have been 

 injured by it ; the combined action of the two ventricles was, on the con- 

 trary,.required, to enable the blood to circulate, along the extensive and 

 tortuous channels of the umbilical cord and placenta. The aorta, on 

 reaching the body of the fourth or fifth lumbar vertebra, divides into the 

 two umbilical arteries; these send to the pelvis and to the lower parts, 

 only very insignificant branches, which convey blood that contains a very 

 small quantity of oxygen ; they then bend along the sides of the bladder, 

 incline inwards, approach towards the urachus, pass out of the abdomen, 

 at the umbilicus, and -joining the umbilical vein which had entered, 

 through the same opening, into the body of the foetus, form with it the 

 umbiiiral cord. 



CCXI. The length of the umbilical cord, measured from the umbili- 

 cus to the placenta, is from twenty to twenty-four inches. It may be not 

 above six inches long, or may greatly exceed that length, as is proved by 

 a case of M. Baudelocque, in which the umbilical cord was fifty-seven 

 inches in length, and passed seven times round the child's neck; which 

 circumstance, by the way, shows that the foetus moves in its mother's 

 womb. Of the three vessels which form the umbilical cord, two, which 

 are the smallest, have an arterial structure, though they convey blood 

 that is truly venous, while the umbilical vein carries arterial blood to the 

 foetus. The umbilical arteries, on reaching the placenta, divide, and are 

 lost in its substance, in a multitude of vessels whose extremities deposit, 

 into the areolae of its tissue, the blood coming from the foetus, and which 

 is to be returned to the mother. Does the course of injection, from the 

 umbilical vein into the arteries, prove that there exists an anastomosis 

 between the extremities of these vessels ? 



The foetus is connected to the mother, by the umbilical cord and placen- 

 ta ; the veins, or the lymphatics of the uteras, and perhaps both these 

 sets of vessels, take up, in the spongy tissue of the placenta, the blood 

 that has been employed In the nutrition of the foetus, and return it to the 

 mother, that, after undergoing a change by the action of her organs, and 

 especially by that of the atmospherical air, by means of the pulmonary 

 circulation, it may become fit for the nourishment of the foetus. Whether 

 we inject the uterine vessels, or whether we force the wax along the um- 

 bilical vein, it never fills but a part of the placenta, which has led to the 

 division of this substance into two parts, the one belonging to the mother, 

 which has been called uterine, the other, called the foetal portion, which 

 forms a part of the umbilical cord. 



The vessels of the mother do not, therefore, anastomose with those of 

 the fretus within the placenta, the circulation is not continued from the 

 one to the other. If the communication were immediate, the beats of 

 the pulse of the child ought to be simultaneous with those of the mother, 

 whereas they are much more frequent, as may be observed, at the time 

 of birth, before the division of the umbilical cord. If the veins of a bitch, 

 ready to whelp, arc opened, the animal dies of hemorrhage, and her body 



