On the Fecundation of the E<j<j in the Common Fowl. 309 



Fig. 10. Oviiiu at a later stage (from ovary). 



Fiij. 11. Styiiu'iitod ovum (from oviduct). 



i'V//. X'l. I'ostorior «vvtri'Uiity of cuibrvo. 



/;V/.i. 1.'5, l-l, 1'), It), llt'ad of embryo in diflV-ront stiiirt's df dovflojimont 

 (seen from bflow) : a, oral pni)ill!i'; h, nwUmmv ; r, alimentHrv 

 caual ; (/, opmiu^r of gulK-t ; c, lateral jn'owtli of mouth ; /, toeth- 

 jiajiilhe ; //, superior {.Towth of moutli. 



X X X \ . — On the Fecundation of the Eijg in the Common Fowl 

 By P. Tasciiek*. 



Ix liis justly celebrated work, 'Illstolre g^n(?rale et particuli^re 

 (hi developpenient ilcs corps organises,' ^I. Co.ste maintains 

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

 being detached from thi.s 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 whei'e the fecundation of the a^^^ takes 

 j)lace mu.st 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 incij)ient 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 Q^^g 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 c^g 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- 

 teiwening between two subsequent eggs and the time occupied 

 by the semen ascending the oviduct. For thi.s purpose I have 

 canied on continuous observations with a consicferable number 

 of hens, noting the exact time when each c^g was laid ; and I 

 have come to the conclusion that the interval between the eg'^s 

 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, panctioned by the author, of an article in the ' Natur- 

 lii.<5tori.<k Tidssjiritt,' Copenliagen, .«er. \\, vol. x. 1875. This paper has 

 obtained a prize from the Koval Danish Societv of Sciences. 



