CHAPTER IV 



CHANGES IN THE OVARY— OOGENESIS— GROWTH 

 OF FOLLICLES— OVULATION— FORMATION OF 

 CORPORA LUTEA AND ATRETIC FOLLICLES— 

 THE SIGNIFICANCE OF THE PROCESTROUS 

 CHANGES IN THE UTERUS 



"The newest freak of the Fallopian tubes and their fimbris3, and the 

 very latest news from the ovisac and the corpora lutea." — John Brown, 

 Horce Subsedvce. 



Development of Ovary and Oogenesis 



The animal egg is a large spheroidal cell consisting of external 

 protoplasm or cytoplasm, a nucleus or germinal vesicle, and a 

 nucleolus or germinal spot.^ Within the cytoplasm is a mass of 



Fig. 23. — Section through ovary of cat. (Schron.) 



1, Outer surface ; 1', attached border ; i, fibrous central stroma ; 3, periphei'al 

 stroma ; 4, blood-vessels ; 5, young follicles ; 6, 7, 8, 9, and 9', larger 

 developing follicles ; 10, corpus luteum. 



food material or yolk (sometimes known as deutoplasm), the quantity 

 of which varies slightly in different Mammalia, and is very con- 

 siderable in birds and certain other animals. The unfertilised ovum 

 differs from the male germ -cell or spermatozoon in its devoting itself 

 mainly to the storage of food-substance and accumulation of potential 



. 1 A'centrosome has been described as present in the ova of some animals. 

 For a detailed description of the ovum in different forms see Wilson, The Cell 

 in Development and Inheritance, 2nd Edition, New Yoz'k, 1900. 



