140 THE PHYSIOLOGY OF REPRODUCTION 



the final maturation of the egg, or the giving off of the polar 

 bodies, awaits in most animals the act of fertilisation. But 

 here the effect is produced upon the egg by the entrance of 

 sperms. How mating and the act of copulation [which is re- 

 peated at frequent intervals every day at this time] could in- 

 fluence the ripening of the egg in the ovary is another problem. 

 In this connection the curious fact must be mentioned that 

 two female pigeons placed in confinement may both take to 

 laying eggs. The 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 pro- 

 ceeds to describe a curious habit which is common among 

 pigeons before copulating. The male bird regurgitates some 

 secretion 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 in- 

 direct stimulation to the female reproductive organs." 



Spallanzani l 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. 2 



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 3 be- 

 lieved that the fimbriated end of the Fallopian tube erected 

 and partially enclosed the ovary. Kehrer 4 suggested that the 



1 Spallanzani, Dissertations, English Translation, London, 1784. 



2 Morgan, The Development of the Frog's E<jf), New York, 1897. 



3 Rouget, " Recbercbes sur les Organes Erectiles de la Femme," Jour, de 

 la Phys., vol. i., 1858. 



4 Kehrer, " Die Zusammenziehungen des Weiblichen Genitalcanals," 

 Beitrdge zur Vergleich. und Exper. (jeburtslcunde, 1864. 



