110 
POPULAR SCIENCE REVIEW. 
PHYSIOLOGY. 
On the Effects of Varnishing the Skin in the Lower Animals. — At least 
since the time of that Pope of Rome who varnished an unfortunate urchin 
into the semblance of a golden child, the fatal effect of coating the skin of 
animals with impermeable varnish has been well known. While a certain 
portion of the skin may be thus coated without producing serious derange- 
ment of the organisation, when the proportion reaches to about one-sixth, 
death can only be avoided by a considerable increase of the temperature in 
which the animal is kept. It was supposed that these phenomena were due 
to the suppression of the functions of the skin, which caused a retention of 
excrementitious matter in the system, giving rise to a form of toxaemia. 
Another explanation, however, of the fatal results produced by body-var- 
nishing was ably advocated in 1868 by Laschkewitch, who attributed 
death to the rapid loss of heat experienced by varnished animals, and this 
view appears until recently to have been very generally received. Latterly, 
however, the older explanation has been supported by Lange and Sakolow, 
which has led M. Lomikowsky to reinvestigate the subject, particularly with 
the object of ascertaining the cause of the rapid decrease of temperature in 
varnished animals. With the help of the thermomultiplier, he has been 
able to prove that the radiation is much greater from varnished than from 
unvarnished animals, the difference being quite sufficient to account for the 
loss of heat and the fall of temperature, while the symptoms observed 
during life and the changes observed in the viscera after death are fully 
accounted for by the cooling, being in fact identical with those found in 
animals killed by exposure to cold. With universal varnishing, as with 
extreme cold, death occurs rapidly, while a more moderate cold or a partial 
varnishing excite inflammatory changes in the internal organs, more par- 
ticularly in the kidneys, and cessation of life indirectly ensues as a conse- 
quence of uraemia. 
ZOOLOGY. 
Reproduction of Hydra. — M. Korotneff has arrived at very different con- 
clusions from those of Kleinenberg upon this subject. According to the 
latter the reproductive cells occur below the ectoderm and form a mass 
which serves for the production of both ova and spermatozoids. The process 
described by him is as follows : one of the cells of this mass increases con- 
siderably and swallows up the surrounding cells, or, in other words, feeds 
upon them. The nucleus then becomes transformed into a germinal vesicle 
and finally the cell comes to represent the ovum of the Hydra which is thus 
in its origin a unicellular and ectodermal formation. The granulations of 
the ovum serve to produce the larger elements described by Kleinenberg 
under the name of pseudo-cells. The blastoderm, according to Kleinenberg, 
is formed immediately after the conclusion of segmentation, and consists of a 
layer of cells forming the whole envelope of the ovum. It is regarded by 
him as an embryonic epithelium, taking no part in the ultimate formation of 
the Hydra , but to be rejected at a certain period of development. Hence the' 
adult Hydra is destitute of epithelium. 
