ANIMALS. 297 



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lical vessels, which consist of a vein and two arteries, issue from 

 the navel of the child, and are branched out upon the placenta ; 

 where they, in fact, seem to form its substance ; and, if I may so 

 express it, to suck up their nourishment from the womb, and the 

 fluids contained therein. The blood thus received from the 

 womb, by the placenta, and communicated by the umbilical vein to 

 the body of the embiyo, is conveyed to the heart ; where, without 

 ever passing into the lungs, as in the born infant, it takes a shor. 

 ter course ; for entering the right auricle of the heart, instead of 

 passing up into the pidmonary artery, it seems to break this 

 partition, and goes directly through the body of the heart, by an 

 opening called the foramen ovale, and from thence to the aorto, 

 or great artery ; by which it is driven into all parts of the body. 

 Thus we see the placenta, in some measure, supplying the 

 place of lungs ; for as the little animal can receive no air by in- 

 spiration, the lungs are therefore useless. But we see the 

 placenta converting the tluid of the womb into blood, and send- 

 ing it, by the umbilical vein, to the heart ; from whence it is 

 despatched by a quicker and shorter circulation through the whole 

 frame. 



In this manner the embryo reposes in the womb ; supplied 

 with that nourishment which is fitted to its necessities, and fur- 

 nished with those organs that are adapted to its situation. As 

 its sensations are but few, its wants are in the same proportion ; 

 and it is probable that a sleep, with scarcely any intervals, marks 

 the earliest period of human life. As the little creature, how- 

 ever, gathers strength and size, it seems to become more wake- 

 ful and uneasy ; even in the womb it begins to feel the want of 

 something it does not possess ; a sensation that seems coeval 

 with man's nature, and never leaves him till he dies. The em- 

 bryo even then begins to struggle for a state more marked by 

 pleasure and pain, and, from about the sixth month, begins to 

 give the mother warning of the greater pain she is yet to endure. 

 The continuation of pregnancy, in woman, is usually nine 

 months ; but there have been many instances when the child has 

 lived that was born at seven ; and some are found to continue 

 pregnant a month above the usual time. When the appointed 

 time approaches, the infant, that has for some months been 

 giving painful proofs of its existence, now begins to increase its 

 efforts for liberty. The head is applied downwaid, to the aper- 



