THE ADVANCE OF BIOLOGY IN 1896. 
C. B. DAVENPORT. 
THE appearance of the second volume of L’ Année Biologigue, 
with its valuable summaries of progress in general biology, 
gives the opportunity for a second summary of progress like 
that published in the WVazuralist last year. 
Cytology. — Five good text-books on this subject appeared 
during the year by Wilson, by Henneguy, by Fol, by Delage 
and Hérouard, and by Zimmermann. The idea of a diversity 
in protoplasmic structure, sometimes fibrillar, sometimes reticu- 
lated, sometimes vacuolated, grew, especially among those who 
at first opposed Biitschli’s foam theory of protoplasmic struc- 
ture. Nadson’s discovery of nuclear matter in Cyanophyces 
was confirmed, with modifications, by Biitschli, who also finds 
it in bacteria. The chemical constitution of the nucleus 
received a little attention. Korschelt classified the chromatin 
as either basichromatin, occurring in one or more large masses, 
or as oxychromatin, occurring as fine granules. The known 
distribution of the centrosome was enlarged, its occurrence 
being recorded for several Protozoa, diatoms, and the ganglionic 
cells of vertebrates and an invertebrate (Lewis). On the other 
hand, Strasburger’s pupils did not find it in tissue cells of 
phenogams. The occurrence of a centrosome in ganglionic 
cells, which are believed not to divide, spoke for its being a 
permanent cell-organ. The true relation of centrosome to 
attraction sphere remained to be elucidated. 
Cell-division was further analyzed. The universal presence 
in the spindle of fibres running from one pole to the other 
became more generally admitted. The discussion over the 
origin of the spindle continued, great deviations from the type 
described for the salamander epithelium were made known, and 
the nuclear origin of the spindle was maintained for both plants 
and animals. Attention was especially directed, by Erlanger and 
1 L’Année Biologique. ager » Yves Delage. Vol. ii, 1896. Paris, Schleicher 
Frères, 1898. Svo., 35 + 808 
