SUMxMAllY OF GUKUKNT KESEARCIIKS. 57 



the sperm and the ovum. There are many (lifficulties in tlie way of the 

 theory that the nucleus lias the monopoly in bearin<^ the hereditary 

 characters. It may be that the generally accepted doctrine of the 

 equivalence of ova and spermatozoa is erroneous. It may be that the 

 common basis of specific characters is to be found in the cytoplasm of 

 the ovum, and that the variable individual characters are borne by the 

 nuclei. It may be that there is a deep division of labour between the 

 two kinds of gametes. 



Implantation of Human Ovum.* — Fr. Delporte has devoted a 

 volume to the embedding of the human ovum in the mucous membrane 

 of the uterus, and the early stages in the formation of the placenta. A 

 young ovum of about ten days is described. The cytotrophoblast plays 

 the leading part in fisation. Langhans's cells penetrate actively into 

 the maternal tissue. The trophoblast is highly developed during the 

 embryotrophic period ; it begins to wane when the haemotrophic 

 period sets in (after the ninth week). 



Corpus luteum and Interstitial Gland of Ovary.f— 0. Van der 



Stricht finds that there are no interstitial cells in the stroma of the ovary 

 of the embryo bat (Vesperugo noctula). They appear some days after 

 birth at the expense of fixed elements of the connective framework. 

 In August and September the first phenomena of follicular atresia are 

 seen ; later on, the parenchymatous cells of the atresic body are trans- 

 formed into interstitial elements, and contribute to a very rapid exten- 

 sion of the interstitial gland. 



Granulations and fatty globules appear in the cytoplasm of the 

 interstitial cells ; a lipoid substance is formed, just as in the corpus 

 luteum. The excreted product accumulates in hollow tubes transformed 

 from solid parenchymatous strands. The process is most active just 

 before and after ovulation. The lipoid glandular product passes out by 

 lymphatic channels. 



The corpus luteum, in great part epithelial, forms first a serous and 

 then a lipoid substance ; the interstitial gland of connective origin 

 forms only a lipoid. Both are endocrinal glands, and the processes of 

 elaboration, secretion, and outflow are the same in the two cases, though 

 the origin of the two structures is quite different. 



Germinal Transplantation. |—W. E. Castle and John C. Philipps 

 are unable to confirm the results reached by Guthrie and Magnus, 

 which seemed to show that transplanted ovaries, in a foreign body, 

 liberate products distinctly influenced in nature by that body. They 

 present a clear case of the transplantation of an undeveloped ovary, 

 which later liberated eggs in the body of a foster-mother, but in the 

 young so produced no foster-mother influence was detectable. (Jreat 

 care has to be taken to make sure that a regenerated ovary is not 

 mistaken for a transplanted ovary. 



* Contributions a I'Etude de la Nidation de I'oeuf humain et de la Physiologie 

 du Trophoblaste. Bruxelles (1912) 206 pp. 



t Arch. Biol., xxvii (1912) pp. 585-722 (2 pis.). 



X Publications Carnegie Inst. Washington, No. 144 (1911) pp. 1-26 (2 pis.). 



