CHANGES IN THE OVARY 



in 



attachment to the broad ligament) as well as numerous blood-vessels. 

 The surface is lined by a layer of columnar epithelial cells. Within 

 are a number of vesicles of various sizes, each with an ovum, 

 surrounded by an epithelium. These are called Graafian follicles'. 

 Certain other structures, consisting of very large yellow-coloured 

 cells enclosed by a branching network of connective tissue, are also 

 often found. These are the corpora lutea or discharged follicles to 



FIG. 25. Section through ovary of rabbit, showing follicles and ova in 

 different stages of development. (L. F. Messel.) 



be described more fully later. The stroma contains, further, a 

 varying number of epithelioid interstitial cells. 



In order to gain a proper understanding of the structural and 

 functional relations of the different parts of the ovary, it is necessary 

 to make some study of its developmental history. 



Piliiger l appears to have been the first to regard the ova 2 and 

 epithelial cells of the Graafian follicles as originating either in the 

 form of ingrowths simulating tubular glands, or as solid columns of 

 cells from that embryonic layer which Waldeyer afterwards designated' 



1 Pfliiger, Ueber die Eierstocke der Saugethiere und des Menschen, Leipzig, 

 1867. 



2 The mammalian ovum .was, discovered by von Baer (Ueber Entwicke- 

 lungsgeschichte der Thiere Beobachtung und Reflexion, vol. i., Konigsberg, 1828). 

 In 1861 Gegenbaur showed that the vertebrate ovum was a single cell. 



