152 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
by either injection. It seems that the poison-gland has continuous secre- 
tion like the liver, and that the details of the process are quite analogous 
to those in ordinary salivary glands. Homogeneous drops appear in the 
cytoplasm, which then becomes clearer ; when the drops are expelled, 
the peripheral parts of the cells become darker. 
Red Blood-Corpuscles of Lamprey.* * * § — Dr. M. C. Dekhuyzen finds 
that these are goblet-like or bell-like. The cell shows a fairly deep 
concavity, — the “ orale Belle,” and there is also a less distinct “ aborale 
Belle.” Thus the “ bell ” may at times appear as a thick biconcave 
disc, as was pointed out by R. Wagner in 1838, and by Gage in 1888. 
In rat, guinea-pig, rabbit, &c., the red blood-corpuscles pass through a 
similar phase, for which the author proposes the term “ Chromokrateren.” 
He has found the same shape in the Pycnogonid Phoxichilidium femo- 
ratum , and he believes that it occurs in some worm-types. Indeed he 
regards the goblet-like shape as ancestral. 
Skin-Glands of Toad.f — Dr. O. Weiss has studied the poison-glands 
in Bufo cinereus. The glandular epithelium is seated on a fine mem- 
brana propria ; then follows a layer of smooth muscle-fibres ; then the 
loose connective tissue of the cutis which surrounds the whole gland. 
By keeping the animals in cold surroundings, he was able to retard the 
mode of secretion, and thus study it in greater detail. The whole pro- 
cess is described. Besides the poison-glands there are mucus-glands, 
aud the two kinds are quite distinct. 
Origin of Myelin.J — Herr R. Wlassak finds that myelin is demon- 
strable in the protoplasm of the spongioblasts in the central nervous 
system of the embryo even before blood-vessels have penetrated. Yet his 
general result is that the myelin is not formed in the nerve-fibre itself, 
but is of exogenous origin. The true source is in the blood, whence the 
myelin passes to the nerve-fibres through the cells of the supporting 
tissue, which has thus a chemical as well as a mechanical function. 
c. General. 
Hature of Life.§ — Dr. G. Mann believes that what constitutes life 
is the presence of a number of “ organic ” compounds, capable of 
mutually reacting on one another, and thus giving rise to new com- 
pounds which, because of their origin, have no further chemical inter- 
action, and therefore form a comparatively stable mantle round the 
unstable or active groups which gave rise to them. The cytoplasm has 
the following functions : — It elaborates food substances so as to make 
them directly assimilable by the nucleus ; it protects the nucleus from 
deleterious influences ; and it either attracts food to the cell or moves 
the cell towards the food. The mantle or envelope of cytoplasm forms 
a new environment which has been created between the chemically active 
groups and the world at large. 
* Anat. Anzeig., xv. (1898) pp. 208-12 (6 figs.). 
t Arch. Mikr. Anat., liii. (1898) pp. 385-96 (3 figs.). 
X Arch. Entwickmech., vi. (1898) pp. 453-93 (4 pis.). See Zool. Centralbl., v. 
(1898) pp. 875-6. 
§ Trans. Oxford Univ. Junior Sci. Club, N.S., No. 6, 1899, pp. 99-101. 
