FECUNDATION. 59 



to be fruitful, must take place within eight or twelve days from the 

 cessation of the menstrual discharge.* Raciborski \ thinks the time more 

 limited. Out of sixteen women who gave him such information as enabled 

 him to determine the time of fecundation, there was only one in whom 

 this occurred so late as ten days after the cessation of the menstrual flux ; 

 and in this one the menses had been suddenly arrested several days before 

 their usual time of cessation, so that the extrusion of the ovum, M. 

 Raciborski thinks, did not take place till about two days prior to the act 

 of sexual intercourse, to which it owed its fecundation. M. Raciborski 

 relates several cases which seem to shew that impregnation may result 

 from sexual coitus taking place one or two days before the period of 

 menstruation. In one of these cases the menses did not appear at all ; in 

 three others they continued an unusually short time. 



OF FECUNDATION.^ 



UNTIL very recently, the opinion prevailed that in every case of im- 

 pregnation, the seminal secretion made its way from the uterus along the 

 Fallopian tubes to the ovary, where its fecundating influence was exerted 

 on the ovum or ova, which were sufficiently mature to be acted upon ; 

 and by many it was also supposed, that unless the seminal fluid reached 

 the ovary, no ova were extruded. Hence the statement of Professor Miil- 

 ler, that in Mammalia, impregnation is always effected at the ovary. 

 Hence also the early remark of Bischoff, that in rabbits a period of from 

 nine to ten hours, in bitches of from twenty to twenty-four hours, after 

 the union of the sexes, elapses before any ova are extruded from the ovary. 

 More recent experiments, made especially by Bischoff || himself, have 

 proved, however, as already related, that the maturation and escape of ova 

 from the ovary, is an event totally independent of the arrival of seminal 

 fluid at the latter organ, and independent even of any union of the sexes. 

 It is true that, as shewn especially by the experiments of Bischoff, sexual 

 union in rabbits, bitches, arid probably most other Mammalia, usually 

 takes place previous to the extrusion of ova from the ovary (though this is 

 denied by M. Pouchet H), and that sufficient time often elapses for the 

 seminal fluid to reach the ovary before such extrusion occurs. Arid, 

 doubtless, in these latter cases, fecundation of the ovum or ova is effected 

 at the ovary itself. But the fact of ova having in several instances been 



* Beweis, p. 44. More recently (Miiller's Archiv. 1844. Jahresbericht, p. 132) Bischoff 

 states as his conclusion from analogical reasoning and facts communicated to him, that the 

 time of fruitfulness is limited to the twelve or fourteen days succeeding each menstrual period. 



t Op. cit. p. 457, etseq. J MUller's Physiology, p. 1488. 



$ Physiology, p. 1491. 



|| Beweis, &c. and Entwiclcelungs-geschichte des Hunde-eies. 



IT Theorie Positive de 1'Evol. Spontan. &c. 1847, p. 372. 



