OP THE MENSTRUA. 349 



pregnancy and for nourishing the foetus.* (A) On the 

 same account, the arteries rather than the veins appear 

 to be the source of the discharge.^ 



558. The investigation of the causes of the periodical 

 return of this hemorrhage is so difficult, that we can 

 obtain nothing beyond probability, and shall not dare 

 to offer any thing merely conjectural, t 



The proximate cause is supposed to be a local § ple- 

 thoric congestion, — an opinion with which the symp- 

 toms preceding menstruation, and the abundance and 

 nature of the uterine vessels, agree very well. 



Among the remote causes may be enumerated the 

 erect posture peculiar to the human race, the peculiar 

 parenchyma of the uterus, and its vita propria. 



It will be better to confess our ignorance of the cause 

 of its periodical return, than to indulge in vain hypo- 



4 



theses : for all the periodical phenomena of health and 



* L. H. Chr. Niemeyer, De menstruationis fine et usu. Gott. 1796. 8vo. 



+ J. Fr. Osiander, on the contrary, argues on the side of the veins, Dim. de 

 fluxu menstruo atque uteri prolapsu. Goett. 1808. 4to. p. 14. 



X Those who feel interested in this enquiry, may consult, among other 

 writers, Abr. D'Orville, Disquisitio (Prses. Haller), causa menstrui fluxus . Got- 

 ting. 1748. 4to. 



Gisb. Verz. Muilman, An ex celebrata hactenus opinione de plethora univer- 

 tali vel particular* vera fluxus menstrui causa explicari possit ? LB. 1772. 4to. 



Theod. Traug. Jaehkel (Prses. Krause), Aetiologia fluxus menstrui. Lips. 

 1784. 4to. 



§ The universal plethoric orgasm, as it was termed, which some formerly 

 regarded as the cause of menstruation, has been long since refuted by more 

 enlightened physiologists. To the arguments of the latter, I may be permitted 

 to add the instance of the celebrated Hungarian sisters formerly mentioned 

 (63. note), who from monstrous formation were united together. Although 

 the same blood flowed in each on account of the union of the abdominal blood- 

 vessels at the loins, they differed frequently both in the period and the quantity 

 of their menstruation. 



