FROM THE OVARIES. 45 



course, and is closely connected with the phenomena of heat in animals, 

 and menstruation in the human female. Bischoff * and Raciborski,t have 

 at length obtained conclusive evidence of the correctness of this view, as 

 far as it regards mammiferous animals. They have also contributed, with 

 many other contemporary writers, to establish the important fact that corpora 

 lutea may be formed under other circumstances than those of impreg- 

 nation. J 



The following is the law of generation which M. Bischoff lays down 

 as applicable both to Mammalia and to man : 



" The ova formed in the ovaries of the females of the human species and 

 mammiferous animals, undergo a periodical maturation, quite independently 

 of the influence of the male seminal fluid. At these periods, known as 

 those of heat ' or the ' rut,' in animals, and ' menstruation ' in the human 

 female, the ova which have become mature disengage themselves from 

 the ovary and are extruded. ' Sexual desire manifests itself in the human 



* Comptes Rendus, 17 Juillet, 1843. Beweis der von der Begattung unabhiingiger perio r 

 dischen Reifung und Loslb'sung der Eier, Giessen, 1844. Translated by Mr. H. Smith, in 

 Med. Gaz., Jan. 3, 17, &c., 1845 



t Comptes Rendus, Seance du 17 Julliet, 1843; and De la Puberte et de Tage critique 

 chez la femme et de la Ponte p6riodique, 8vo. Paris, 1844, p. 405, et seq. 



J Malpighi, and many other Italian writers after him, asserted that the ova were not only 

 formed, but also discharged from the ovaries, previous to, and independently of, fecundation or 

 tlie union of the sexes ; both their formation and their discharge being effected by the agency 

 of corpora lutea, which these writers regarded as glands produced in the ovaries, even of 

 virgin animals, for that purpose. The ova, when discharged, became impregnated, Malpighi 

 believed, either in the Fallopian tube, or in the uterus. (Malpighi, Opera Omnia, 4to. Lugd. 

 Batav., 1687, p. 222-224). 



These views were opposed by Haller, who maintained that the ova of quadrupeds and the 

 human female, are separated from the ovaries, and corpora lutea formed, only in consequence 

 of impregnation ; and the weight of Mailer's opinion had caused Malpighi's theory, and the 

 facts he announced to be neglected, at all events, in this country, when, in 1817 Sir Everard 

 Home re-produced them as new discoveries. (Lectures on Comparative Anatomy, vol. iv. p. 

 297. Philos. Transactions, 1817, p. 25, 1819, p. 59.) Sir E. Home gave Malpighi's theory 

 a more complete form, stated the facts on which it was based more precisely, and also 

 connected the discharge of the ova with the phenomena of heat and menstruation, which 

 Malpighi had not done. 



Four years later Dr. Power published an Essay on the Nature and Causes of Menstrua- 

 tion, (Essays on the Female Economy, London, 1821,) in which he endeavoured to shew 

 from analogical reasoning and the facts observed by physiologists; 1st. that Menstruation is 

 an effect of the state of orgasm which arises in the ovaries every month; 2nd. that this state 

 of the ovaries is connected with the maturation of the ova, which successively reach maturity 

 after intervals of a lunar month; 3rd. that the mature ovum, if impregnation does not take 

 place, usually perishes within the ovarium, and is removed by the process of absorption ; but 

 4th. that the vascular action in the ovary may, independently of sexual intercourse, be suffi- 

 ciently great to cause the expulsion of the ovum, and 5th. that in this case a corpus luteum 

 will be formed as a cicatrix of the ruptured Graafian vesicle. 



The discovery of the unimpregnated ova in the Graafian follicles of mammiferous animals, 

 by Von Baer, in 1827, afforded a basis for more accurate investigations of the phenomena of 

 1 mpregnation, and of the circumstances under which ova may be discharged from the ovary. 



