476 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
characteristics of living organisms, reproduction being regarded as the 
result of growth and assimilation rather than as a prime characteristic 
of living things. The theory of vital force has been recently urged from 
the chemical point of view by Prof. Japp, and from the physical by 
Mr. Alfred Earl. Prof. Weiss believes that chemists will ultimately 
succeed in producing organic substances having the asymmetry of 
natural products, and in the meantime does not regard the argument 
derived from chemistry as of great value. 
Mr. Earl’s biological argument is based upon the apparent existence 
of an element of choice in the movements and feeding of living organisms. 
As to the latter, Prof. Weiss points out that species of Fucus growing in 
similar conditions do not absorb similar amounts of potassium and 
calcium, so that two different vital forces must be at work even in plants 
so nearly allied. He believes that the progress of knowledge will show 
that what appears to be choice is merely the result of complex chemical 
processes. He believes, similarly, that the movements of animals and 
plants are due to mechanical, physical, and chemical changes in their 
protoplasm, and that the belief in a vital force tends rather to retard than 
to advance scientific progress. 
Evolution of Scales of Lizards.* — Herr A. Sokolowsky has studied 
the scales of Lacertilia in connection with the probable phylogeny of the 
class. He comes to the conclusion that all the forms may be referred, 
back to simple papillae with radial growth, as seen in geckos. Vestiges 
of this primitive condition are still to be seen in forms with highly 
developed scales. 
Osmotic Peculiarities of Cells.t — Herr E. Overton publishes a pre- 
liminary account of his investigations on this subject. By a series of 
experiments on root-hairs, he finds that those substances which are more 
soluble in ether, fatty oils, and similar media than in water, are capable 
of penetrating through living protoplasm with great rapidity, while those 
which are slightly or not at all soluble in ether and fatty oils, pene- 
trate the protoplasm either very slowly or not at all. He believes that 
this is explicable only on the supposition that the superficial layer of 
protoplasm is imj)regnated with a substance having the solvent pro- 
perties of a fatty oil. Various facts are against the supposition that the 
substance can be itself a fatty oil, and the author believes that it is 
cholesterin or a cholesterin compound, and that this explains the 
universal distribution of this substance. Such animal cells as possess 
vacuoles filled with cell-sap display the same plasmolytic phenomena as 
plant cells. The osmotic peculiarities of other animal cells were studied 
by placing amphibian tadpoles in various solutions. By a combination 
of observation and deduction the author convinced himself that their 
cells react in the same way as do plant cells. A remarkable circum- 
stance with regard to Amphibians and certain fish, is that the epithelial 
cells are permeable to water in one direction only, that is, from within 
outwards, and not in the reverse direction, for the osmotic pressure of 
the blood is much higher than that of the surrounding water, and yet 
water does not pass into the blood system. Nevertheless, the author 
* Zurich, 1899, 56 pp., 1 pi. See Zool. Centralbl., vi. (1899) pp. 415-8. 
t Vierteljahrschr. Nat. Ges. Zurich, xliv. (1899) pp. 88-135. 
