22 LEO LOEB. 



(6) No. 755. One day, nineteen hours after copulation, left 

 uterus ligatured; extirpate one corpus luteum in left ovary; six 

 days later extirpate one corpus luteum of the right ovary. Ex- 

 amination of ovaries and uterus eighteen days after copulation. 

 Pregnancy was not present. A new ovulation had taken place 

 approximately two days previously, to judge from the condition 

 of the ovaries. The uterus showed high cylindrical epithelium 

 of the surface and of the gland ducts; in both many mitoses were 

 present; some polynuclear leucocytes are in the lumen of some 

 glands. In the connective tissue there are small nuclei present 

 without mitoses. Some cells migrate through the surface 

 epithelium. 



We see in these as well as in other similar cases which we 

 need not mention here, a parellelism between the condition of 

 the ovaries and the uterus. An experimentally accelerated 

 ovulation leads to the onset of a new cycle in the uterine 

 mucosa. 



IV. THE UTERUS OF PREGNANT GUINEA-PIGS IN WHICH AFTER 



EXCISION OF THE CORPORA LUTEA A NEW 



OVULATION HAD TAKEN PLACE. 



As we stated in former papers during pregnancy no new ovu- 

 lation takes place in the ovary of the guinea-pig. 1 However, 

 after excision of the corpora lutea within the first week after 

 copulation in a considerable number of cases, a new ovulation 

 takes place notwithstanding the presence of pregnancy. 2 We 

 saw that if in a non-pregnant guinea-pig an accelerated ovulation 

 takes place after an early extirpation of the corpora lutea, the 

 uterine mucosa undergoes the typical changes characteristic of 

 the stage of the sexual cycle at which the examination had been 

 made. It is different, if a new ovulation takes place in pregnant 

 guinea-pigs, as the following observations demonstrate: 



(i) No. 748. Twenty-one hours after copulation ligature and 

 cut left tube at juncture with uterus, cut out one corpus luteum 

 in the left ovary. Seven days after copulation, cut out one corpus 



1 "The Cyclic Changes in the Uterus of the Guinea-Pig, "Journal of Morphology, 

 Vol. 22, p. 37, 1911; Virchows Arch., Vol. 206, 1911. 



2 Deutsche Med. Wochenschrifl, 1911, No. I. 



