"262 Mr. Walter Heape. Ovulation and ‘| Mar. 6, 
e 
between them. It appears obvious that thus the supply of ovarian nutriment 
‘is stopped. About nine hours after copulation maturation of the ovum takes 
place and two polar bodies are rapidly formed. 
It is of interest to notice that maturation does not occur until after the 
‘supply of nutriment to the ovum is cut off, for in this particular it appears 
‘probable that the formation of polar bodies takes place under conditions of 
nutriment essentially different from those which prevail during segmentation. 
Ovulation.—About 10 hours after copulation the Graafian vesicle ruptures 
‘through the attenuated wall which projects on the surface of the ovary. The 
ovum, entirely freed from the discus proligerus cells, is shot out into the 
infundibulum which now closely invests the ovary. 
Once freed from the ovary the mature ovum is Incapable of assimilating 
nutriment unless it be fertilised ; if from any cause fertilisation is not effected 
‘the ovum quickly dies, although it is bathed in the nutrient material supplied 
‘by the maternal tissues ; ova thus degenerating are, from time to time, to be 
-seen in the fallopian tubes. 
It is necessary then, in the case of rabbits at any rate, that spermatozoa 
-should be present in the fallopian tubes, and I find that as a rule they are to 
‘be found at the top of the uterus horn two hours after copulation and close to 
-the infundibulum, if not actually within its folds, four hours after copulation. 
In those animals in which the ovum does not undergo maturation in the 
ovary, the presence of spermatozoa at the top of the fallopian tube is not 
necessary. In the mouse, for instance (No. 29), when the ovum is dehisced 
from the ovary it is not free from discus cells, and the polar body may be 
formed during its passage down the fallopian tube. 
Recently it has been shown (No. 23) that in the ferret ovulation does not 
take place without previous copulation, the same is also said of the pig and 
sheep (No. 11, cf also, No. 22) and guinea-pig (No. 26), and I suspect it will 
also be found to be true for other animals. It is interesting to note that 
ovulation in the frog takes place only when a certain stage of maturation is 
reached (No. 24). The fact that maturation of the ovum does not occur until 
after copulation has taken place affects fundamentally the results of various 
experiments which have been made on artificial fertilisation of rabbit’s ova 
{Nos. 10, 25, 28). Epil 
The Rupture of the Follicle and the Corpus Lutcum.—The cause which 
induces the rupture of the Graafian vesicle is obscure. Immediately before 
rupture the wall of tle distended follicle where it projects on the surface of 
the ovary is very thin, and is covered by a thin layer of the tunic of the 
ovary.. The congested vessels which surround the follicle are present also 
‘between the follicle and the tunic of the ovary in this distended portion. 
