46 DISCHARGE OF OVA 



female with greater intensity at these periods, and in the females of mam- 

 miferous animals at no other time. If the union of the sexes takes place, 

 the ovum is fecundated by the direct action of the semen upon it. If no 

 union of the sexes occurs, the ovum is nevertheless extruded from the 

 ovary, and enters the Fallopian tube ; but there perishes. The relation in 

 respect of time between the extrusion of the ovum, and its fecundation by 

 the semen, may vary to a certain extent ; and the limits of this variation 

 seem to be different in different animals. The seminal fluid may have 

 time to reach the ovary before the ovum is extruded ; or the ovum may 

 escape first, and afterwards meet the semen in the Fallopian tube. But the 

 fecundating influence of the semen must be exerted on the ovum before 

 it has quite passed through this tube, otherwise development will not take 

 place ; for the development of the ovum commences in the Fallopian tube. 

 It is only at the time of the periodical maturation of the ova that sexual 

 union can have impregnation for its result." * 



M. Bischoff also maintains, in common with other recent writers, that 

 the discharge of ova at the periods of heat or menstruation, always gives 

 rise to the formation of corpora lutea. 



It may be useful to examine the evidence on which these views respect- 

 ing the maturation and discharge of ova, and the formation of corpora 

 lutea are based. 



Ova are matured and discharged from the ovary independently of im- 

 pregnation and sexual intercourse; and their discharge takes place periodi- 

 cally, namely, at the periods of heat in animals, and menstruation in the 

 human female. 



With respect to mammiferous animals, lower than man, these statements 

 are undoubtedly correct. In the first place, there is ample evidence to 



Nevertheless, until very recently, but little addition was made to our knowledge on these 

 subjects. The theory of Malpighi, in the modified form which it received from Sir E. Home 

 and Dr. Power, was reasserted with more or less distinctness, by Dr. Lee, in 1834 (Cyclo- 

 pedia of Practical Medicine, Art. Ovary.), M. Gendrin, in 1839 (Traite Philosophique de 

 Medecine Pratique, torn. i. p. 28, et seq.\ Dr. W.Jones, in 1839 (Practical Observations 

 on Diseases of Women, London, p. 157, et seq.). M. Negrier, in 1840 (Recherches Anatom. 

 et Physiol. sur les Ovaries, Paris), Dr. Paterson, in 1840 (Edinburgh Med. and Surg. Jour- 

 nal, vol. 53, p. 62), Mr. Girdwood (Lancet, 1842-1843, vol. i. p. 825), and M. Pouchet, in 

 1842 (ThSorie Positive de la F^condation, Paris). 



But although facts of great interest had been adduced by many of these authors, in 

 support of their theory, and had been detailed by them with more accuracy than by the 

 earlier writers, yet these facts were not in their nature new, and were not generally received 

 as conclusive proofs. M. Bischoff and M. Raciborski were the first to apply the light 

 afforded by Baer's discovery to the elucidation of this subject, and to demonstrate the 

 unimpregnated ovum of a mammiferous animal in the Fallopian tube, after its escape from 

 the Graafian follicle. The observations of M. Bischoff and those of M. Raciborski, were 

 published at the same time, but the descriptions given by the former are much the more 

 detailed and precise. 



* Beweis, &c., p. 4. 



