103 



CHAPTER III. 



History of Gestation. 



261. If the fecundated or conceived ovum passes out of the organs 

 of the mother before the germ begins its development, as in birds, 

 there is no gestation, and the animal is called oviparous. If the 

 embryo is formed while passing through the oviduct, but so that it 

 cannot separate itself from its shell until after it is laid, as in certain 

 reptiles, there is still, properly speaking, no gestation, and such ani- 

 mals are called ovo-viviparous. Whenever, on the contrary, the egg 

 undergoes its entire incubation in the interior of the generative sys- 

 tem, and the foetus is not expelled until the development of its organs 

 enables it to live and grow in the external world, pregnancy or ges- 

 tation is said to exist; this is observed to take place in the mammi- 

 ferae only; in this case there exists a gestative organ, a single uterus, 

 or one womb and two ad uterum, destined to lodge the product of 

 fecundation until it attains its maturity, and such animals are deno- 

 minated viviparous. 



Pregnancy, in the human species, is one of the phenomena of re- 

 production which it most imports us carefully to study. The words 

 pregnancy and gestation are not synonymous witli the words preg- 

 nant woman or woman with child. The former express a function 

 and all that appertains thereto, from its origin until its termination. 

 The latter indicate merely the actual state of a woman who contains 

 within herself a fecundated or conceived ovum. 



262. Division. If the fecundated ovum reaches, without being ob- 

 structed, the cavity of the womb, and maintains itself there, the preg- 

 nancy is said to be good, natural, or uterine; if it remains and is devel- 

 oped in the ovary, if it falls into the cavity of the peritoneum, stops in 

 the Fallopian tube, or becomes engaged in the substance of the womb 

 itself, it on the contrary receives the title of bad, preternatural, or 

 extra-uterine. The first species is then divided into three varieties. 



1. Simple pregnancy where the womb contains only a single ovum. 



2. Double, triple, quadruple, or compound pregnancy, when there 



