106 PLAIN FACTS FOR OLD AND YOUNG 



Development in the Higher Animals and Man. — 



Higher anunals are less prolific, and their development 

 is a more complicated process ; hence, their young need 

 greater protection; and for this reason, the ova, in- 

 stead of being discharged from the body of the female 

 after fecundation, are retained. 



Curious examples of internal development some- 

 times occur in animals which usually deposit eggs. 

 Snakes have been known to produce both eggs and liv- 

 ing young at the same time. At the annual meeting of 

 the American Society for the Advancement of Science, 

 at Detroit, Mich., in August, 1875, we had the pleasure 

 of examining a specimen, exhibited by Professor 

 Wilder, of a chick which had undergone a considerable 

 degree of development within the ovary of the hen. It 

 had a head, a rudimentary brain, and internal viscera, 

 but no feathers nor limbs. It was, in fact, an egg 

 hatched before it had been laid. The anomaly excited 

 much interest at that time, and since, among biologists. 



As we have seen that a suitable receptacle is some- 

 times provided outside of the body, so now a recepta- 

 cle is needed, and is provided in the interior of the 

 body of the female. This receptacle is called— 



The Uterus.— This is a hollow, pear-shaped organ, 

 located in the median line, just behind the bladder, 

 between it and the rectum. It is supported in place 

 by various ligaments, and by the juxtaposition of other 

 organs. Its larger end is directed upward, and com- 

 municates upon each side with a very narrow tube, 

 which is prolonged outward on either side until it 

 nearly touches the ovary of the same side. Its lower 

 and smaller end fills the internal extremity of the pas- 

 sage previously described as the vagina. When the 

 ovum is matured, it escapes from the ovary into the 



