392 Mr. E. S. Carmichael and Dr. F. H. A. Marshall. [Apr. 10, 



Stress has also been laid upon the well-known fact that whereas the 

 corpora lutea of the ovary continue to undergo development for a considerable 

 period of time if pregnancy supervene after ovulation, this hypertrophy soon 

 ceases in the absence of pregnancy. Bond records an experiment on a rabbit 

 in which the ovary after being grafted to an abnormal position contained a 

 somewhat aberrant " corpus luteum of pregnancy " in association with a 

 gravid uterus. Such observations are regarded by him as affording evidence 

 of an internal uterine secretion (differing from that elaborated by the 

 ancestrous uterus), acting on the ovaries and so inducing a growth of luteal 

 tissue. It must be remembered, however, that the occurrence of pregnancy 

 •exercises a profound effect over the whole maternal organism, and not merely 

 supon the condition of the ovaries. 



Certain other authors have adopted views which imply a dependence of the 

 ovaries upon some function of the uterus. Thus, Loewenthal (1884) appears 

 to have held that ovulation occurs as a result of a stimulus in some way set 

 up by the uterine changes of the procestrum. Moreover, Heape (1900) has 

 expressed the belief that oestrus (which depends normally upon the presence 

 of the ovaries) "is possible only after the active changes due to procestrum 

 have taken place in the uterus," but this statement clearly applies to normal 

 animals. 



Excepting for the two experiments of Bond, which have just been referred 

 to, no experimental work appears to have been published upon the effects of 

 .hysterectomy on the ovaries. The following experiments, therefore, notwith- 

 standing the fact that the results reached were negative, are not without 

 importance. 



Experiment 1. — On April 8 the uterus was removed entire from a very 

 young rabbit which weighed 420 grammes. On August 8 the weight was 

 1640 grammes. The rabbit was killed on November 11 after being weighed. 

 The weight was then 2060 grammes, the animal being apparently fully 

 grown. The ovaries were well developed, having increased greatly in size 

 since the operation. On histological examination they were found to be 

 normal, containing numerous growing Graafian follicles, and showing no signs 

 whatever of degeneration. 



Experiment 2. — On April 8, the uterus of a very young rabbit was 

 removed, excepting the cervix. Weight, 390 grammes. On August 8 the 

 weight was 1640 grammes. On November 11 the rabbit was killed. 

 Weight, 1940 grammes. The ovaries were normal in every way. 



Experiment 3. — On May 2 the uterus was removed entire from a young 

 xabbit. Weight, 650 grammes. On August 8 the weight was 1660 grammes. 

 The rabbit was put with the buck at intervals and noticed to copulate. On 



