868 THE AMERICAN NATURALIST. (VoL XXXII. 
Henneguy, towards the accessory cell bodies («« Nebenkerne”’), 
of which several kinds, differing in origin, were distinguished. 
The idea that amitosis in a cell sounds its death knell was 
opposed by strong cases. 
Experiments to control cell-division were multiplied. The 
well-known hastening of cell-division by heat was observed 
again. Induced electric currents provoked direct division in 
salamander epithelium, and determined that the dividing plane 
should be transverse to the current (Galeotti). Norman con- 
firmed Loeb’s assertion, that in dense solutions cytoplasmic 
cleavage might be inhibited without interfering with nuclear 
division. Boveri showed that in a cleavage sphere containing 
archoplasm, but no chromatin, division of the archoplasm might 
continue in the absence of chromatin. The independence of 
nucleus and cytoplasm grew more evident. 
The Sexual Products and Fecundation.— Chromatin reduction 
was observed in Heliozoa (Schaudinn) and Coccidiidze (Labbé) — 
thus among the simplest organisms. The history of the origin 
of the sex-cells and their periods of multiplication and of rest 
were traced by Eigenmann in a viviparous fish. The question 
of the locus of the centrosome in the spermatozoon was under- 
going debate. As for fecundation, the belief that the archoplasm 
of the female plays no part in egg-cleavage was unanimously 
confirmed by the several workers upon this subject. 
Parthenogenesis. — The observation of last year on the 
absence of true parthenogenesis in the unfertilized eggs of 
the higher vertebrates was confirmed. Parthenogenesis in the 
lower algze was induced artificially. It was stated (Zur Strassen) 
that two eggs of Ascaris may fuse, giving rise to a zygote 
capable of developing into a giant embryo. 
Asexual Reproduction. — New cases of reproduction by 
autotomy were described for a holothurian and a nemertean. 
Attention was again called (by Seeliger) to the non-parallelism 
between budding and egg-ontogeny, and Ritter insisted on the 
origin of buds in Tunicates from embryonic tissue. 
Ontogenesis. — The truth that in development preformation 
and epigenesis are blended, which was dawning in 1895, became 
still clearer as a result of the work of 1896. Especially was 
