;i70 OF CONCEPTION 



among the other great changes of the sexual organs, the 

 enlargement of the vesicles. Nay we are certain that it will 

 occasion the rupture of the vesicle without any commerce with 

 the male. The hens of poultry lay eggs (incapable indeed of 

 being hatched), although separated from the cock, a circum- 

 stance proving that in them the o?strum is sufficient to enlarge 

 and burst a vesicle, apply the tube to the ovarium, and occa- 

 sion it to convey away an ovum. Aristotle and Harvey relate 

 that many birds lay eggs from mere titillation ; the latter proved 

 it experimentally in the thrush, in the sparrow, and in a favorite 

 parrot belonging to his wife. Blumenbach* is satisfied with the 

 accuracy of the accounts which he has read of corpora lutea in 

 virgins, and since he wrote we have been furnished with abun- 

 dant instances of their appearance in virgins not only of our 

 own kind but of quadrupeds. Sir Everard Home f asserts that 

 the corpus luteum is not a formation that fills up the cavity of a 

 ruptured vesicle, but a substance in which the ovum is produced, 

 tmd consequently no proof of conception. However this may be, 

 the case remains the same ; for he has repeatedly seen ovaria of 

 both human and quadruped virgins that had discharged ova. 

 Indeed he revives the old opinion of Kerckring, \ that ova are 

 continually growing to maturity in succession and discharged. 

 On this point I find it difficult in the present state of our know- 

 ledge to make up my mind, but I think it pretty evident that, 

 although the semen has no share in bursting the ovarium, the 

 high excitement of copulation contributes very considerably to 

 it, since the inferior degree of excitement which occurs during 

 the heat of brutes and in the lascivious states of the human 



great size. Blancaard, Schurig, Brendelius, Santorini, and Drelincourt, men- 

 tion analogous facts. Hnller's uotes to Boerhaave's Pr&lect. sltad. 



* Spec. Physiol. &c. anno 1788. quoted in his note to 562. 



f Phil. Traits. 1819, 



I Anthrop. Icknogr. 1. 3. and 12. quoted by Schurig. "Tarn conjugate 

 qwain vVrgines hsec ova saepissime excernunt, insensibiliter quidem, quia non 

 t, nee quicquam <le iis siippk'antur." 



