KARYOKINESIS AND ITS RELATION TO FERTILIZATION, 215 
Karyokinesis and its Relation to the Process of 
Fertilization. 
By 
WwW, Waldeyer.! 
With Plate XIV. 
if. 
As to the relation which the process of karyokinesis 
bears to fertilization and heredity, I propose to discuss 
two memoirs, one of which I have frequently quoted already : 
—‘ Recherches sur la maturation de l’ceuf, la fécondation et 
la division cellulaire,’ by E. van Beneden, Gand, Leipzig and 
Paris, 1883. The second is more recent, A. Weismann, 
‘ Ueber die Zahl der Richtungskorper und iiber ihre Bedeutung 
fiir die Vererbung, Jena, 1887. 
EK. van Beneden’s memoir, which is amongst the most 
prominent phenomena of recent biological literature, traces 
the formation of spermatozoa and eggs, together with the 
phenomena of fertilization in the great thread-worm of the 
horse, Ascaris megalocephala, which, indeed, seems des- 
tined to be become a classic object for these matters. I here 
pass over the account of sperm- and egg-formation, although 
it contains an abundance of new and valuable knowledge, in 
order to deal with the phenomenon of impregnation, and the 
important part which karyokinesis plays in the process. 
With respect to fertilization, it was known that a 
‘fusion ”’ (copulation) occurs between the head of the sper- 
1 Translated by W. B. Benham, D.Sc., from the ‘Arch. fiir mikr. Anat.,’ 
vol. xxxii, 1888, pp. 1—12. 
VOL, XXX, PART 3.—NEW SER. P 
