On the Fecundation of the Egg in the Common Fowl. 369 



JFicf. 10. Ovum at a later stage (from ovary). 



I'lff. 11. Segmented ovum (from oviduct). 



Fif/. 12. Posterior extremitj' of embrj'o. 



Fit/s. 13, 14, 15, 16. Head of embryo in different stages of development 

 (seen from belovp) : a, oral papilke ; b, antenna ; c, alimentary 

 canal ; d, opening of gullet ; e, lateral gi-owth of mouth ; /' teeth- 

 papillae ; ff, superior gTOwth of mouth. 



XXXV. — On the Fecundation of the Egg in the Common Fowl. 

 By P. Tascher*. 



In his justly celebrated work, 'Histoire g^nerale et particuli^re 

 clu ddveloppement des corps organises/ M. Coste maintains 

 that the egg of the hen is fecundated in the ovary long before 

 being detached from this organ, and that a number of eggs are 

 fecundated at one and the same time. 



The latter of these assertions has been subjected to searching- 

 criticism by subsequent authors, and shown to be untenable ,• 

 but the question as to where the fecundation of the egg takes 

 place must still be considered an open one. Coste founds his 

 conclusion partly on the microscopical appearance of not a few 

 eggs in the ovary itself, indicating an incipient degeneration 

 (a circumstance which does not, however, seem to prove the 

 point, inasmuch as the process in question need not be caused 

 by non-fertilization), and partly on certain experiments 

 with hens which, after having been kept isolated, were 

 paired 42 hours before an egg could be expected to be laid, 

 assuming that exactly 48 hours elapse between the laying of 

 each egg in the regular course. According to M. Coste, the 

 egg requires 30 hours to pass from the ovary through the 

 whole length of the oviduct ; and his hens would consequently 

 have been paired just 12 hours before the next egg was de- 

 tached from the ovary; but in 12 hours the semen would, in 

 in his opinion, reach the ovary. In order to control this rea- 

 soning it is clearly necessary to verify carefully the time in- 

 tervening between two subsequent eggs and the time occupied 

 by the semen ascending the oviduct. For this purpose I have 

 can-ied on continuous observations with a considerable number 

 of hens, noting the exact time when each egg was laid ; and I 

 have come to the conclusion that the interval between the eggs 

 is more correctly 44-46 hours in the case of hens laying every 

 second day, and 26 hours in the case of those which lay every 



* Abstract, sanctioned by the author, of an article in the 'Natur- 

 historisk Tidsskrift,' Copenhagen, ser. 3, vol. x. 1875. This paper has 

 obtained a prize from the Royal Danish Society of Sciences. 



