SIZE, WEIGHT, AND POSITION OF THE FCETUS. 449 



At the seventh week, the embryon measures about nine 

 lines. Points of ossification have appeared in the clavicle 

 and the lower jaw ; the Wolffian bodies are large ; the pedicle 

 of the umbilical vesicle is very much reduced in size ; the 

 internal organs of generation have just appeared ; the liver 

 is of large size ; the lungs present several lobules. 



At the eighth week, the embryon is from ten to fifteen 

 lines in length. The lungs begin to receive a small quantity 

 of blood from the pulmonary arteries ; the external organs 

 of generation have appeared, but it is difficult to determine 

 the sex ; the abdominal walls have closed over in front. 



At the third month, the embryon is from two to two and 

 a half inches long, and weighs about one ounce. The amni- 

 otic fluid is then more abundant, in proportion to the size of 

 the embryon, than at any other period. The umbilical cord 

 begins to be twisted ; the various glandular organs of the ab- 

 domen appear ; the pupillary membrane is formed ; the limi- 

 tation of the placenta has become distinct. At this time, the 

 upper part of the embryon is relatively much larger than the 

 lower portion. 



At the end of the fourth month, the embryon becomes 

 the foetus. It is then from four to five inches long, and 

 weighs about five ounces. The muscles begin to manifest con- 

 tractility ; the eyes, mouth, and nose are closed ; the gall-blad- 

 der is just developed ; the f ontanelles and sutures are wide. 



At the fifth month, the foetus is from nine to twelve 

 inches long, and weighs from five to nine ounces. The hairs 

 begin to app'ear on the head ; the liver begins to secrete bile, 

 and the meconium appears in the intestinal canal ; the amnion 

 is in contact with the chorion. 



At the sixth month, the foetus is from eleven to fourteen 

 inches long, and weighs from one and a half to two pounds. 

 If born at this time, life may continue for a few moments ; 

 the bones of the head are ossified, but the fontanelles and 

 sutures are still wide ; the prepuce has appeared ; the testi 

 cles have not descended. 



