ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
397 
tions. Among these we note that in the red blood-corpuscles of birds 
and amphibians, and in the marrow of mammals, he finds a fine nuclear 
reticulum, which stains with eosin. The reticulum shows minute en- 
largements at the intersections of its threads. The author identifies it 
with the achromatin-reticulum. As the cytoplasm and the nuclear mem- 
brane also stain with eosin, he emphasises the continuity of cytoplasmic 
and nuclear material. 
Granular Leucocytes.* — Dr. G. L. Gulland has, during the past 
seven years, accumulated a mass of material consisting of everything 
which bears upon the study of leucocytes. These bodies must be fixed by 
reagents, of which the best is sublimate, if we desire to examine their 
finer structure. 
The author thinks that it is impossible to divide leucocytes into a 
haemal variety and a coelomic variety, for (1) lymphocytes are the pre- 
cursors of all forms ; (2) leucocytes are not present in the blood in 
early foetal life ; (3) they are constantly passing from blood to connec- 
tive tissue, and vice versa ; (4) the mitotic reproduction of leucocytes 
takes place almost entirely in adenoid tissue. All varieties of leuco- 
cytes are merely stages in the development of a tissue. They may be 
divided for convenience, and with regard to the presence or absence of 
granules, into three main groups, the hyaline, acidophile, and basophile. 
These forms are all derived from the lymphocytes, which are the 
daughter-cells derived from the mitosis of all leucocytes. 
The author is of opinion that the granules of leucocytes are not 
products of the metabolic activity of the cell imbedded in a structureless 
protoplasm, as was hitherto supposed, but represent an altered condition 
of the microsomes. They always form part of the cytomitoma, and are 
therefore plasmatic, and not paraplastic. They are probably concerned 
with amoeboid movement, and they and the rest of the mitoma are more 
visible, the more active the cell. In diseased conditions it is utterly 
impossible to say what organ is affected, from the kind of leucocytes 
present in excess in the blood. 
Muscle-Spindles and Nerve-Endings.j — Dr. Chr. Sihler describes 
the simple muscle-spindles of snakes and the more complex, but more 
familiar, muscle-spindles of the frog, and interprets both as the sensory 
end-organs of the muscles. 
A terminal plate is a composite organ. It consists of a number of 
fine terminal fibres, each of which is surrounded for some distance by 
Henle’s sheath, which may still exhibit a nucleus. The proper terminal 
fibres often show nuclei corresponding to those of Schwann’s sheath, 
and bear Endbeeren enclosed in a sheath of protoplasm. Besides these 
there are often 4-6 so-called “ sole-nuclei.” Thus there are three 
different sets of nuclei. 
Sympathetic Ganglion-Cells of the Frog4 — Dr. A. Dehler finds 
that the sympathetic ganglion-cells of the frog must be ranked among 
those cells which, even in the resting stage, show central bodies and a 
centered cytoplasmic structure. He has demonstrated a central-corpuscle- 
* Journ. Physiol., xix. (1896) pp. 385-417 (2 pis.). 
t Arch. f. Mikr. Anat., xlvi. (1895) pp. 709-23 (1 pi.). 
X Tom. cit., pp. 724-39 (1 pi.). 
