394 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
by Chun. Dr. Driesch, starting with the fact that it has been proved 
that isolated cleavage cells may produce an entire organism, sought to 
find where the limits of this power appear in the subsequent stage 
of development. He appears to have soon come to a state in which the 
primitive tendency of cells to replace others in the formation of organs 
becomes lost. Herr Herlizka succeeded in tying a thread about the 
eggs of Triton cristatus in such a way as to completely separate the first 
two cleavage cells. 
Experimental Teratogeny.* — Dr. F. Supino has some general notes 
on this subject, and describes a double and a tbree-eyed trout. He sub- 
mitted trout ova to the influence of an induction current, but the results 
showed little beyond a debilitating and dwarfing of the young. For the 
causes of monstrosities in the strict sense, Supino looks to organismal 
rather than to environmental conditions. 
Atlas of the Fertilisation and Xaryokinesis of the Ovum.f — Prof. 
E. B. Wilson, with the aid of Dr. E. Learning, has prepared a most 
instructive and valuable atlas of the fertilisation and karyokinesis of 
the ovum. It is the object of this work to place before teachers and 
students of Biology a series of figures photographed directly from nature, 
to illustrate some of the principal phenomena in the fertilisation and early 
development of the animal ovum. While the discoveries of recent years 
must in some measure be dealt with by every text-book on the subject^ 
they belong to a region of observation inaccessible to the general reader 
or student, since they can only be approached by means of a refined 
histological technique applied to special objects. No drawing, it is 
remarked, can convey an accurate mental picture of the real object. The 
photograph, whatever be its shortcoming, at least gives an absolutely 
unbiassed representation of what appears under the Microscope. The 
eggs selected were those of the common sea urchin Toxopneustes varie- 
gatns. These have the great advantage of being devoid of pigment and 
very transparent, so that nuclei, asters, and spindles can be clearly seen, 
and their history followed in life. The general results of Prof. Wilson’s 
investigations are entirely opposed to those of Fol on every essential 
point. With regard to the bearings of his observations on the general 
question of inheritance, they seem, if accurate, to afford a conclusive 
demonstration that the archoplasm is not concerned in inheritance, 
since it is derived from one sex only. These investigations thus remove 
some of the objections that have been urged against the nuclear theory 
of inheritance, and confirm the view of Boveri that the archoplasm is 
essentially a dynamic element of the cell, concerned with cell-division. 
They indicate further, in the author’s opinion, that neither the archo- 
plasm nor the centrosome can in any proper sense be regarded as a 
necessary and constant element of the cell. 
Reviewing this atlas, Prof. W. F. R. Weldon, J under the suggestive 
title of “ The photography of histological evidence,” makes some 
interesting and valuable remarks on the real value of photography. 
He comes to the conclusion that, when photography has done its best, 
* Bull. Soc. Veneto-Trent. Sci. Nat., vi. (1896) pp. 43-9 (3 figs.). 
f New York, 1895, large 4to, 32 pp., 10 photo, plates, 20 figs. See also Proc. 
Boston Soc. Nat. Hist., xxvi. (1895) pp. 469-73. 
X Nature, liv. (1896) p. 73. 
