KARYOKINESIS AND ITS RELATION TO FERTILIZATION. 249 
to be able to speak with perfect certainty about the one or the 
other, even when we take count of the beautiful researches 
of Strasburger on the fertilization of Phanerogams, Jena, 1884. 
On this point cf. also Flemming’s assertions (61) and Prings- 
heim’s statements, ‘ Sitzungsber. d. k. Preuss. Akad. d. Wis- 
senschaften zu Berlin,’ 1882, June 2. 
Nussbaum (Il. c.) regards fertilization as essentially a con- 
jugation of cells. I do not think, at least, that Nussbaum 
can be quoted as a decided champion of pure nuclear fertiliza- 
tion, as Kolliker does (‘ Zeit. f. wiss. Zool.,’? Bd. xlii, p. 516). 
K. van Beneden, whilst he formerly left it somewhat doubtful, 
says quite decidedly in his most recent work, that the proto- 
plasmic portion of the spermatozoon of Ascaris megaloce- 
phala takes no share in fertilization (“Il résulte avec une 
absolute certitude de l’étude du développement de l’Ascaris, 
que le corps protoplasmique du spermatozoide dégenére et 
mintervient pas dans l’édification du corps protoplasmique de 
la premiére cellule embryonnaire que le noyau du zoosperme 
est le seul élément paternel fourni a lceuf féconde”’). But, 
in fact, if it is so held, as E. van Beneden describes, that the 
protoplasmic portion of the zoosperm disappears in the pro- 
toplasm of the egg-cell without a trace; then the male proto- 
plasm unites, if not formally, yet materially, with the female 
protoplasm. Is this altogether without significance? Matters 
would be different if, during the entrance of the spermatozoon 
into the egg, the protoplasmic portion of the former became 
separated in any way, and did not reach the egg. We find, 
too, the statement by Platner, as previously mentioned, that 
the protoplasmic portion of the spermatozoon reaches the egg 
and behaves in accordance with van Beneden’s account for 
Ascaris, viz. it separates itself completely from the nuclear 
element of the zoosperm and loses itself in the egg-protoplasm : 
accordingly a material fusion of both sorts of protoplasm occurs 
here also. 
J. Frenzel, who also assigns to the protoplasm a share in 
fertilization, relies on the existence of non-nucleated lower 
forms of life, such as the Bacteria. I must, however, confess 
