CHANGES IN THE OVARY 135 



function of ovulation is in a state of tension, so to speak, that 

 requires only a slight stimulus, 'mental' apparently in this case, 

 to set the mechanism to working. At any rate, it is impossible to 

 regard the presence of sperm in the oviduct as an essential element 

 of the stimulus to ovulation, although it may have an important 

 influence in the normal case. Our attention is directed to the 

 various and complex instincts of the male which come under the 

 head of courtship, both before and after mating is effected, as 

 furnishing a part of the stimulus to the female reproductive organs." 

 Harper proceeds to describe a curious habit which is common among 

 pigeons before copulating. The male bird regurgitates some secre- 

 tion in its throat, and this is taken up by the bill of the female in 

 much the same manner as the young take their food. " It is easy 

 to see that here may be one of the sources of indirect stimulation 

 to the female reproductive organs." 



Spallanzani ^ found that whereas the female fire-bellied toad could 

 lay its eggs in the absence of the male, the female fetid toad, if 

 isolated, retained its eggs in the ovaries. The common frog is 

 capable of spontaneous oviposition, at least in some cases.^ 



' The exact nature of the mechanism by means of which the 

 discharged ova in the human female are made to pass into the 

 aperture of the oviduct is not certainly known. Rouget^ believed 

 that the fimbriated end of the Fallopian tube erected and partially 

 enclosed the ovary. Kehrer* suggested that the ovum was shot 

 into the open fimbriaj in the act of ejaculation. The motion of the 

 cilia, which line the fimbriated end as well as the interior of the 

 tube, no doubt serve to set up a current which assists in directing 

 the ova. The fimbria^ therefore, act as an aspirator. Gerhardt,^ who 

 has paid some attention to the question, concludes that in man and 

 many other Primates a number of factors co-operate to secure the 

 entry of the discharged ovum into the tube. These factors include 

 the erectibility of the fimbrife, the muscular movements of the same, 

 the ciliary currents on the fimbrife and tube, and the configuration 

 'of the ovarian surface. In other orders of Mammals the process is 

 brought about in various ways. In Monotremes, Marsupials, and 

 Cetaceans the entrance to the tube is relatively large as compared 

 with the size of the ovary. In certain other animals a portion of 



' Spallanzani, DisseHations, English Translation, London, 1784. 



2 Morgan, The Development of the Frog's Egg, New York, 1897. 



^ Eouget, " "Recherches sur les Organes Erectiles de la Femme," Jotir. de 

 la Phys., vol. i., 1858. 



^ Kehrer, " Die Zusammenziehungen des Weiblichen Genitalcanals," Beitrage 

 zuT Vergleieh. und Exper. Geburtskunde, 1864. 



* Gerhardt, " Studien iLber den Geschlechtsapparat der Weiblichen Sauge- 

 thiere : I. Die Ueberleitung des Eies in die Tuben," Jenaische Zeitsch., 

 vol. xxxix., 1905. 



