
1905. | Physiology of Mammalian Reproduction. 397 
employed to a considerable extent for disorders associated with the female 
- generative organs, and in the majority of cases is said to have produced 
beneficial results. This method of treatment, however, is in many cases 
purely empirical and is adopted without regard to the condition of the ovaries 
from which the extract is obtained. 
Several investigators have experimented with ovarian grafts both in normal 
and abnormal positions. From some of these experiments it would appear 
that portions of ovarian tissue may obtain vascular connections, and produce 
an effect on the general metabolism comparable to that produced by ovaries 
in normal animals. 
It has been shown by Goltz and others that the occurrence of cestrus is not 
due entirely to cerebral or spinal reflexes. Our experiments have demon- 
strated that “heat,” or a transient condition resembling it, can be produced 
by the injection of extracts made from ovaries in a procestrous or cestrous 
condition, and that when such ovaries are successfully grafted into an animal 
previously deprived of its ovaries, the condition produced is identical with a 
normal heat, and that irrespective of the situation of the graft. 
The Function of the Corpus Lutewm.—Of the various theories as to the 
function of the corpus luteum, that of Fraenkel is the only one that is 
supported by experimental evidence. According to this theory the corpus 
luteum is the only ovarian organ of internal secretion, and exerts an influence 
on the generative functions generally throughout the whole reproductive 
period of the animal’s life. Among its other functions, according to this 
theory, it produces heat and menstruation and controls the attachment of the 
ovum and the formation of the placenta. This theory is only partially correct 
Corpora lutea are not present during the procestrum and are therefore only 
functional subsequent to ovulation. 
From our own experiments upon bitches and rats we draw the conclusion 
that the presence of luteal tissue is necessary during the first part of 
pregnancy, but that the corpus luteum ceases to be functional during the 
later stages. In these experiments we removed the ovaries from animals at 
various intervals after impregnation, and found that pregnancy did not 
continue, except in those cases in which the operation was performed in the 
later stages of pregnancy. Control experiments in which the ovaries were 
damaged or partially removed were also performed, when it was found that the 
animals brought forth young. 
General Conclusions—The ovary is an organ providing an internal secretion 
which is elaborated by the follicular epithelial cells or by the interstitial cells 
of the stroma. This secretion circulating in the blood induces menstruation 
and heat. After ovulation, which takes place during cestrus, the corpus 
