728 SCIENCE PROGRESS 



The Functions of the Corpus Luteum 



Various views have been advanced as to the functions of this 

 gland, and it is proposed to deal briefly with some of the older 

 ones before passing to the' two most recent. 



The first is that the corpus luteum forms a plug of tissue to 

 fill up the cavity of the ruptured follicle and so compensate for 

 the disturbance in the circulatory system caused by the rupture. 

 A second view, really a modification of the former, is that it 

 provides a soft tissue which favours the growth of the succeeding 

 follicles and allows of the regrowth of blood vessels instead of 

 leaving hard fibrous scar tissue. These views have met with 

 little support. Although just after rupture the corpus luteum is 

 smaller than the follicle, it ultimately grows and becomes a great 

 deal larger and also possesses an elaborate and highly specialised 

 histological structure. Again, no blood vessel with the structure 

 of an arteriole or venule is ever found in the corpus. In view 

 of these facts the foregoing explanations of its functions are 

 obviously insufficient. 



Another theory that has received a considerable amount of 

 support owes its origin to Beard (3). In an interesting paper in 

 1897 ne suggested that the function of the corpus luteum Was 

 to suppress ovulation during pregnancy by causing the degenera- 

 tion of the nearly ripe follicles and retarding the maturation of 

 the others. He stated also that it disappeared prior to parturi- 

 tion in order to allow of ovulation at that time, but it only 

 effected a temporary suppression in the absence of pregnancy, 

 hence the difference in duration between the corpus luteum 

 verum and the corpus luteum spurium. In a large number of 

 animals, however, the corpus luteum has not disappeared before 

 parturition. The suggestion is open to several other criticisms, 

 however. Follicles may mature in an ovary that has large and 

 active corpora lutea. The rabbit can ovulate shortly after 

 parturition, indeed by some observers it is stated to do so 

 spontaneously at that time, but well-marked corpora lutea are 

 still present in the ovary. Again, in the rabbit and sometimes 

 also in the sheep and ferret and probably in other mammals the 

 follicles do not burst spontaneously, and in the absence of 

 copulation degenerate on their own account without ever coming 

 under the influence of a corpus luteum. In certain mammals 

 only one batch of follicles reach maturity during the breeding 



