112 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
acknowledges liis indebtedness to Prof. Oscar Hertwig’s “invaluable 
book,” but tbc rapid advance of discovery bas made it seem desirable 
to amplify tbe original plan of the work. It does not profess to be an 
exhaustive account of the cell, but to consider those features that seem 
more important and suggestive to the student of development. The 
author fears that the botanists will complain of gaps. 
Prof. Wilson concludes with a glossary, which will not only be 
useful to those who have forgotten their Greek, but to the student of 
the history of the subject, as in nearly all cases the name of the author 
of the term and the date of its invention aro added. 
Blood of Lamprey.* * * § — Dr. E. Giglio-Tos finds that the red blocd- 
corpuscles of the lamprey are unusually simple, like young stages, in 
fact. They are spherical vesicles, filled with haemoglobin in sparse 
cytoplasm. They are derived from erythroblasts, within which haemo- 
globin-forming granules — of nuclear origin — appear as usual. The 
erythroblasts in circulation show no indirect division, but in rare cases 
may divide directly. The erythrocytes do not divide. 
Leucocytes with simple nucleus and leucocytes with polymorphic 
nucleus arise from similar leucoblasts, which multiply by direct division. 
The fine “neutrophilous” granulations of the leucocytes with poly 
morphic nuclei are probably of nuclear origin. The amitotic nuclear 
division of these adult leucocytes is not followed by cell-division. 
New Nerve-Sheath.^ — Dr. A. Ruffini describes in the terminal tract 
of peripheral nerve-fibres a new sheath — the subsidiary sheath — which 
occurs between Henle’s sheath and Schwann’s. 
Centrosomes and Attraction-Spheres in Leucocytes of Newt.i — 
Dr. R. Marchesini finds that the centrosome and its attractive sphere 
have a quite definite form and occurrence. Even in the resting cell they 
have a direct relation with tbe nucleus, and may perhaps be regarded as 
a differentiation of the same. He believes that they not only preside 
over division, but have to do with plasmic movements and the nutrition 
of the cell. By using a mixture of malachite and saffranin greens he 
was able to differentiate the centrosome and its sphere instantaneously 
while the cell was still living. 
Minute Structure of Ganoid Scales.§— Dr. H. Scupin has studied 
the scales of a large number of fossil Ganoids. His chief results are the 
following : — The enamel is no necessary component of the Ganoid-scale, 
and may be absent in otherwise typical Ganoids. The interpretation of 
the “ lepidine tubes ” of Williamson as traces of connective tissue fibrils is 
confirmed. In the various families of Ganoids the minute structure of 
the scales is usually characteristic. The degeneration of the enamel in 
the Rhynchodontidae makes it necessary to separate this family from the 
others included in the sub-order of Lepidosteidei ; the nearest relations 
are rather with the Saurodontidae. 
* Mem. R. Accad. Sci. Torino, xlvi. (1896) pp. 219-52 (1 pi.), 
f Anat. Anzeig., xii. (1896) pp. 467-70 (1 fig.), 
t Boll. Soc. Korn. Stud. Zool., v. (1896) pp. 89-96 (1 pi.). 
§ Arch. f. Naturges., lxii. (1896) pp. 145-86 (2 pis.). 
