SUMMARY OF CURRENT RESEARCHES 
RELATING TO 
ZOOLOGY AND BOTANY 
(principally invertebrata and oryptogamia), 
MICROSCOPY, Etc. 
Including Original Communications from Fellows and Others .* 
ZOOLOGY. 
VERTEBRATA. 
a. Embryology. f 
Experimental Embryology 4 — MM. Charrin and Gley have shown 
that toxin-injection of rabbits results in abnormalities in the skeletal 
system of the progeny. They show that chemical conditions may 
produce malformations similar to those usually traceable to physical 
factors. 
Blastodermic Vesicle of Pig.§ — Mr. A. W. Weysse describes as the 
earliest stage observed a blastodermic vesicle consisting of a sharply 
defined inner layer of flattened cells (endoderm), forming a closed sac, 
and an outer layer of nearly isodiametric cells (ectoderm), thickened at 
one point to form the germinal disc. The thickening is due both to an 
increase in the diameter of the cells at right angles to the surface, and 
to an increase in the number of cell layers. On the outside of the 
ectoderm is found here and there a Deckschiclit ” cell, apparently in 
process of disintegration. 
As the embryo develops, the germinal disc grows by a multiplication 
of cells ; the area covered by the disc is, however, thickened rather than 
extended. While the disc increases in thickness, the proliferation of 
cells at the posterior end continues, producing a distinct upfolding or 
overgrowth in that region, and at the same time a similar process has 
been going on at the two lateral margins. Soon these three overgrowths 
meet and fuse, forming one continuous bridge, at first attached at only 
three points, but later coming in contact with the disc at all points of 
* The Society are not intended to be denoted by the editorial “ we,” and they do 
not hold themselves responsible for the views of the authors of the papers noted, 
nor for any claim to novelty or otherwise made by them. The object of this part of 
the Journal is to present a summary of the papers as actually published , and to 
describe and illustrate Instruments, Apparatus, &c., which are either new or have 
not been previously described in this country. 
f This section includes not only papers relating to Embryology properly so called, 
but also those dealing with Evolution, Development and Reproduction, and allied 
subjects. X Comptes Rendus, cxxi. (1895) pp. 664-6. 
§ Proc. Amer. Acad. Sci., xxii. (1895) pp. 283-321 (4 pis.). 
