262 ELEMENTS OF HISTOLOGY. [Chap. xxxn. 



this process of degeneration involves also follicles of 

 smaller sizes. 



350. Before menstruation, generally one, occasion- 

 ally two or more, of the ripe follicles become very 

 hypersemic. They grow, in consequence, very rapidly 

 in size ; their liquor folliculi increases to such a degree 

 that they reach the surface of the ovary ; finally 

 i.e., during menstruation they burst at a superficial 

 point ; the ovum, with its discus proligerus, is ejected, 

 and brought into the abdominal ostium of the oviduct. 

 The cavity of the follicle collapses, and a certain 

 amount of blood, derived from the broken capillaries 

 of the wall of the follicle, is effused into it. The follicle 

 is converted into a corpus luteum, by an active multi- 

 plication of the cells of the granulosa. New capilla- 

 ries with connective tissue cells derived from the theca 

 folliculi externa gradually grow into the interior, i.e., 

 between the cells of the granulosa. This growth 

 gradually fills the follicle, except the centre ; this 

 contains blood-pigment in the shape of granules, 

 chiefly contained in large cells, and a few new 

 blood-vessels, the blood-pigment being the remains 

 of the original blood effused into the follicle. 

 But, ultimately, the pigment all disappears, and a 

 sort of gelatinous tissue occupies the centre, while 

 the periphery i.e., the greater part of the follicle 

 is made up of the hypertrophied granulosa, with 

 young capillary vessels between its cells. The 

 granulosa cells undergo fatty degeneration, becoming 

 filled with several small fat globules, which gradually 

 become confluent into a big globule. In this state the 

 corpus luteum is complete, and has reached the height 

 of its progressive growth. The tissue is then gradually 

 absorbed, and cicatrical tissue is left. When this 

 shrinks it produces a shrinking of the corpus luteum. 

 This represents the last stage in the life of a 

 Graafian follicle. The corpus luteum of Graafian 



