424 Mr. Hammond and Dr. Marshall. Correlation between 



extent as when pregnancy supervenes, but on the other hand undergoes 

 retrogression after a few days. Ancel and Bouin, however, assert that in 

 such animals as the rabbit the corpus luteum, when formed, undergoes the 

 same amount of hypertrophy irrespective of the occurrence of gestation, 

 and that since these animals do not normally ovulate excepting after coition 

 the presence of corpora lutea is nearly always associated with the pregnant 

 condition. Further, they put forward the view, for which a considerable 

 body of evidence has been adduced, that in such animals as the rabbit the 

 corpora lutea provide the exciting cause for the growth of the mammary 

 glands during the first part of pregnancy. 



In order to test this hypothesis they carried out experiments in which 

 the Graafian follicles of rabbits were ruptured under such conditions that 

 pregnancy could not supervene. The method usually adopted was to ligature 

 the vasa deferentia of the male rabbits. This operation although inhibiting 

 pregnancy, since spermatozoa cannot be ejaculated, does not prevent the 

 occurrence of coition. Since coition without seminal ejaculation is generally 

 sufficient to induce ovulation in the doe, corpora lutea could be formed just 

 as though pregnancy had supervened. Ancel and Bouin found that the 

 growth of the corpora lutea produced in this way was accompanied by a 

 hypertrophy of the mammary glands which continued for about 15 days or 

 until the corpora lutea began to undergo retrogressive changes. It was 

 naturally concluded that the growth of the mammary glands was brought 

 about by the activity of the corpora lutea. The further development of the 

 mammary glands in pregnant rabbits is ascribed by Ancel and Bouin to the 

 activity of a different gland, which is described as lying between the stroma 

 and muscular layers of the uterus, and is designated the myometrial gland. 



Frank and Unger have described a case of a virgin rabbit with corpora 

 lutea in the ovaries and a breast development such as is usually characteristic 

 of the end of the first third of pregnancy. 



Furthermore, O'Donoghue has investigated the relation of artificially 

 produced corpora lutea to the mammary glands. He took female rabbits in 

 a condition of oestrus, and ruptured the Graafian follicles mechanically. 

 In many cases corpora lutea were formed, and when this happened their 

 presence was associated with a growth of the mammary glands. The amount 

 of growth in 14 or 15 days is stated to have been about equivalent to that 

 shown by the normal pregnant rabbit in 12 days. If, however, the artificial 

 rupture of the follicles was not followed by the formation of corpora lutea 

 the mammary glands did not show any hypertrophy. O'Donoghue had 

 previously adduced evidence that the corpora lutea and mammary glands are 

 functionally correlated in Dasyxirus. 



