REPRODUCTIVE SYSTEM OF THE FEMALE 57 



An extreme form of preformationism was advocated by certain thinkers 

 during this period. For example. Bonnet championed the idea of encasement 

 or "emboitement." To quote from Bonnet: 



The term "emboitement" suggests an idea which is not altogether correct. The 

 germs are not enclosed Hke boxes or cases one within the other, but a germ forms 

 part of another germ as a seed is a part of the plant on which it develops. This 

 seed encloses a small plant which also has its seeds, in each of which is found a 

 plantule of corresponding smallness. This plantule itself has its seeds and the latter 

 bears plantules incomparably smaller, and so on, and the whole of this ever 

 diminishing series of organized beings formed a part of the first plant, and thus 

 arose its first growths. (Cole, '30, p. 99.) 



On the other hand, there were those who maintained that for some animals, 

 neither the sperm nor the egg were important as "many animals are bred 

 without seed and arise from filth and corruption, such as mice, rats, snails, 

 shell fish, caterpillars, moths, weevils, frogs, and eels" (Cole, '30, p. 38). 

 This concept was a part of the theory of spontaneous generation of living 

 organisms — a theory ably disproved by the experimental contributions of 

 three men: Redi (1626-97); Spallanzani; and Louis Pasteur (1822-95). 



Modern embryology embraces a kind of preformationism, a preforma- 

 tionism which does not see the formed parts of the new individual within 

 the egg or sperm but which does see within the egg a vital, profound, and 

 highly complex physiochemical organization capable of producing a new in- 

 dividual by a gradual process of development. This organization, this self- 

 determining mechanism, is resident in the nucleus with its genes and the 

 organized cytoplasm of the fully developed oocyte or egg. However, as shown 

 later, this organization is dependent upon a series of activating agencies or 

 substances for its ultimate realization. Some of these activating substances 

 come from without, but many of them are produced within the developing 

 organism itself. 



C. General Structure of the Reproductive System of the Vertebrate Female 



1. General Structure of the Ovary 



Morphologically, the ovary presents a series of contrasts in the different 

 vertebrate classes. In teleost fishes the size of the ovary is enormous compared 

 to the body of the female (fig. 28), while in the human (fig. 29), cow, sow, 

 etc., it is a small structure in comparison to the adult body. Again, it may 

 contain millions of mature eggs in the ling, cod and conger, during each breed- 

 ing season, wherons only a single egg commonly is matured at a time in the 

 cow, elephant, or human. During the reproductive season the ovary may 

 assume a condition of striking colored effects as in the bird, reptile, shark, 

 and frog, only to recede into an appearance drab, shrunken, and disheveled 

 in the non-breeding season. 



