49 i SUMMARY OF CURRENT RESEARCHES RELATING TO 
Corpus luteum of Mouse.* — Dr. J. Sobotta comes to the following 
conclusions. The ripe follicle, apart from ovum and discus proligerus, 
consists of a follicular epithelium of several layers and showing mitoses, 
and of the theca folliculi which consists of an abundantly cellular inner, 
and a more fibrous outer layer. During or after the bursting of the 
follicle there is usually no bleeding. A newly burst follicle is dis- 
tinguished from one which is ripe only by the absence of follicular fluid 
and the ovum with the discus proligerus. 
About an hour after bursting, the cells of the inner theca layer 
begin to divide mitotically, while the mitoses in the epithelium cease. 
It no considerable bleeding has occurred, there is a gradual exudation 
of serous fluid, and migrant cells appear in the inner theca layer. 
Some five to seven hours after bursting, the proliferating process in 
the theca-cells gives rise to radial connective strands which penetrate 
the epithelium, the cells of which gradually increase. In the formation of 
the connective-tissue strands the inner theca layer is gradually used up, 
and leucocytes now abound in the epithelium. 
In the 40-50tli hour there is a finer distribution of the connective- 
tissue within the epithelium, which may be accompanied with further 
growth of the epithelial cells. The wandering cells and connective 
tissue form a network around the central exsudation which is gradually 
absorbed. After completed absorption a gelatinous connective kernel 
remains wdthin the corpus luteum. 
Some 60-72 hours after the bursting of the follicle, the epithelial 
cells grow to about ten times their previous volume and are surrounded 
by group 3 of anastomosing connective-tissue cells. At the same time 
abundant capillaries arise, but leucocytes are absent. The prolifera- 
tion of connective-tissue ceases, and the corpus luteum takes its final 
form. Fat-granules afterwards appear in the much enlarged epithelial 
cells. 
Each follicle which bursts forms a true corpus luteum even when 
the ovum is not discharged. There is no degeneration of the corpus 
luteum in the mouse. The corpora lutea are at first greyish-red, and 
subsequently yellow ; they attain to a size many times larger than the 
ripe follicle. The characteristic epithelial portion of the corpus luteum 
arises by simple hypertrophic increase of the original follicular epithe- 
lium, the connective tissue from a proliferation of the inner theca layer, 
and partly from leucocytes. 
Development of Hypophysis.f — Prof. J. Nusbaum finds, from a 
study of dog embryos, that the hypophysis vesicle is connected, on the 
one hand, by the stalk with the mouth-cavity, and, on the other 
hand, by the modified Sessel’s pouch with that portion of the pharyn- 
geal cavity which corresponds to the embryonic pharynx. Thus, 
besides the direct communication between pharyngeal cavity and outer 
world via the mouth, there is another, indirect, not altogether open con- 
nection between the pharynx and mouth by an arch, the limbs of which 
are the proper hypophysial evagination and Sessel’s pouch. He com- 
pares this discovery with what is known in Myxine, Petromyzon, sturgeon, 
opossum, &c. 
* Arch. f. Mikr. Anat., xlvii. (1896) pp. 261-308 (3 pis.), 
t Anat. Anzeig., xii. (1896) pp. 161-7 (4 figs.). 
