KARYOKINESIS AND ITS RELATION TO FERTILIZATION. 159 
Karyokinesis and its Relation to the Process of 
Fertilization. 
By 
Ww. Waldeyer.! 
With Plate XIV. 
Tur phenomenon which is indicated by the name “ Karyoki- 
nesis” depends essentially on the appearance of distinctly 
visible and readily stained thread-like structures in the cell- 
nucleus, which change their form during its division. These 
structures were observed and figured before they were recog- 
nised as general and important occurrences. For example, 
Henle in his ‘ Splanchnologie’ (1865, p. 355) gave the first 
drawings of karyokinetic figures for cells of the testis. Again, 
Heller and A. Kowalevsky (1869), and later on W. Krause 
(1870)—if we here leave out of consideration botanical 
writers—-may be added as observers of facts in karyokinesis, 
without, however, giving a correct explanation of them. The 
honour of discovering karyokinetic (indirect, metamorphic or 
mitotic) nuclear division as a regular phenomenon, with its 
three chief constituents—chromatic nuclear figure, achromatic 
spindle and polar stars—belongs to A. Schneider, the zoologist 
of Breslau, at that time in Giessen. In his memoir, “ Unter- 
suchungen wber Platyelminthen,”’ in the ‘Jahrb. der ober- 
hessische Gesellschaft fiir Natur- und Heilkunde’ (1873), he 
describes facts about the division of egg- and sperm-cells, as 
1 Translated by W. B. Benham, D.Sc., from the ‘ Arch. fiir Mikr. Anat.,’ 
vol. xxxii, 1888, pp. 1—123 
VOL, XXX, PART 2,—NEW SER, if 
