ANIMALS. IP 



upon the fingers and toes ; and the stomach and intestines already be 

 gin to perform their functions of receiving and digesting. In the sto 

 mach is found a liquor similar to that in which the embryo floats ; in 

 one part of the intestines, a milky substance ; and in the other, an ex- 

 crementitious. There is found also a small quantity of bile in the 

 gall bladder ; and some urine in its own proper receptacle. By this 

 time also, the posture of the embryo seems to be determined. The 

 head is bent forward, so that the chin seems to rest upon its breast; 

 the knees are raised up towards the head, and the legs bent backward, 

 somewhat resembling the posture of those who sit on their haunches. 

 Sometimes the knees are raised so high as to touch the cheeks, and 

 the feet are crossed over each other ; the arms are laid upon the 

 breast, while one of the hands, and often both, touch the visage ; 

 sometimes the hands are shut, and sometimes also the arms are found 

 hanging down by the body. These are the most usual postures which 

 the embrvo assumes ; but these it is frequently known to change ; and 

 it is owing to these alterations that the mother so frequently feels those 

 twitches which are usually attended with pain. 



The embryo, thus situated, is furnished by nature with all things 

 proper for its support ; and, as it increases in size, its nourishment also 

 is found to increase with it. As soon as it first begins to grow in the 

 womb, that receptacle, from being very small, grows larger; and, what 

 is more surprising, thicker every day. The sides of a bladder, as we 

 know, the more they are distended, the more they become thin. But 

 here the larger the womb grows, the more it appears to thicken. 

 Within this the embryo is still farther involved, in two membranes, 

 called the chorion and amnios ; and floats in a thin transparent fluid, 

 upon which it seems, in some measure, to subsist. However, the great 

 storehouse, from whence its chief nourishment is supplied, is called 

 the placenta ; a red substance somewhat resembling a sponge, that 

 adheres to the inside of the womb, and communicates, by the umbi- 

 lical vessels, with the embryo. These umbilical vessels, which con- 

 sist 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 nour- 

 ishment from the womb, and the fluids contained therein. The blood 

 thus received from the womb, by the placenta, and communicated by 

 ihe umbilical vein to the body of the embryo, is conveyed to the 

 heart ; where, without ever passing into the lungs, as in the born in- 

 fant, it takes a shorter course ; for entering the right auricle of the 

 heart, instead of passing up into the pulmonary 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 aorta, 

 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 inspiration, the lungs are 

 therefore useless. But we see the placenta converting the fluid of thu 

 womb into blood, and sending it, by the umbilical vein, to the heart ; 

 from whence it is dispatched by a quicker and shorter circulating 

 through the whole framp. 

 VOL. I. M 



