240 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Action of Corpus luteum on Mammary Glands.* — P. Bourn and 

 P. Ancel have shown that the development of the mammary gland in 

 pregnancy is due to the influence of the corpus luteum, and, further- 

 more, that there is another influence exerted by the same body, which 

 has the effect of sensitizing the glandular cells so that they respond to 

 another factor (normally a specific hormone), and begin to secrete. 



Artificial Production of Corpora lutea.f — Chas. H. O'Donoghue 

 corroborates the observation of Ancel and Bouin that artificial bursting 

 of the ripe follicles in a rabbit may be followed by the formation of the 

 corpora lutea. He found, however, that this was not invariable. If the 

 rupture of the follicles was followed by the formation of corpora lutea, 

 there was also a growth of the mammary glands. The amount of growth 

 in fourteen or fifteen days was about equal to that in the normal 

 pregnant female of twelve days. On the other hand, if the follicular 

 rupture was not succeeded by the formation of corpora lutea, then there 

 was no growth of the mammary glands, although the operation per- 

 formed had been precisely the same in the two cases. 



Corpus luteum in Marsupials.J— Chas. H. O'Donoghue has studied 

 the corpus luteum in Perameles obesula, P. nasuta, Macropus ruficollis, 

 Petrogale penicillata, and Phascolomys wombat. In these species the 

 ovaries have far fewer corpora lntea than the ovary of Dasyurus viver- 

 rinus has ; the wall of the ripe follicle has the same structure as in 

 D. viverrinus or in higher mammals ; the formation of the corpus 

 luteum in P. obesula, P. nasuta, and M. ruficollis is similar to that 

 described for D. viverrinus ; the structure of the fully formed corpus 

 luteum in P. penicillata and P. wombat is as in related species ; the 

 corpus luteum spurium is precisely identical with the corpus luteum 

 verum ; in the ovaries of II. ruficollis, P . penicillata, and P. wombat, 

 but not in P. obesula and P. nasuta, there are degenerating corpora 

 lutea or corpora fibrosa, which probably disappear through the agency 

 of leucocytes. 



The lutein cells are derived exclusively from the cells of the mem- 

 brana granulosa, while the proliferations of the theca folliculi (both 

 theca interna and theca externa) give origin only to the connective- 

 tissue of the corpus luteum. In P. obesula and P. nasuta the lutein 

 cells multiply by mitosis. A corpus luteum also occurs in the duckmole. 

 That of the Marsupials examined is not distinguishable from, nor 

 inferior to that of Eutheria. 



Regeneration of Testes in Birds. §— C. J. Bond has studied the 

 consequences of orchectomy in fowls and pigeons. When the testis is 

 removed intra-capsularly, a regeneration of the secret! ng-tissue of the 

 testis and the tubuli seminiferi takes place within the emptied capsule. 

 This regeneration must take place from the capsule, or, more probably, 

 from microscopic fragments of secreting-tissue which are left adhering 



* C.R. Soc. Biol. Paris, lxxvi. (1914) pp. 150-3. 



t Ex Journ. Physiol., xlvi. (Feb. 15, 1913) 1 p. 



t Arch. Mikr. Anat., lxxxiv. (1914) 2te Abt., pp. 1-47 (4 pis. and 1 fig.). 



§ Journ. Genetics, iii. (1913) pp. 131-9 (2 pis. and 9 figs.). 



