ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
617 
of his views in a recent essay by Dr. Pfeifer ; the identity of argument 
strengthens Haacke’s position. While many are puzzled to find any 
evidence that acquired characters are inherited, Haacke assures us that 
if we consider the organism aright we shall be convinced that they 
must be. 
Heredity and Development.* * * § — Dr. W. Haacke distinguishes patho- 
logical variations, in which organic structure has, as it were, undergone 
dislocation, from non-pathological variations, in which the disturbance 
of equilibrium is followed by an adaptive restoration. He criticises 
the various current conceptions of heredity — e. g. those of Haeckel, 
Hertwig, De Tries, Driesch, Roux, and Weismann. One of his criticisms 
is summed up in the sentence that, according to Weismann, heredity 
is the accidental correspondence of child to parent. He himself believes 
in a genetic continuity of germ-cells from generation to generation, but 
also in a material continuity between germ-cells and body. As the 
organism is a system in equilibrium, changes in the body must affect 
the germ-cells also. The relations of equilibrium, original and acquired, 
are transmitted. And these relations of equilibrium are best explained 
on the theory of gemmaria. 
Osmotic Phenomena in Plants and Animals. f — Herr E. Overton 
indicates provisionally some of the more important results of his pro- 
longed researches. He sketches the historical development of our 
knowledge of osmosis, from Nollet and Dutrochet to Nageli and Pfeffer, 
and explains how the impermeability of protoplasm, or of the outer 
cytoplasmic layer, to many crystalloids is the condition of the high 
osmotic pressure exhibited by living cells. The tabular records of his 
experiments illustrate the fact that there are the same relations between 
osmotic pressure, volume of the solution, and molecular weight, as 
obtain in the case of gases. But his most important result is that all 
cells agree in being readily permeable by solutions of simple alcohols, 
ether, chloroform, simple aldehydes, acetone, and many other com- 
pounds. He indicates the application of this fact in physiology, experi- 
mental embryology, medicine, and so on, but we defer further report 
until the full paper is published. 
Influence of the Environment .{ — M. L. Cuenot first discusses the 
influence of primary environmental factors — heat, light, food, &c., on 
•organisms. A second chapter is devoted to the influence of environment 
on reproduction, sex, and development. He concludes with a discussion 
on faunistic adaptations. The book is admirably terse and clear, and is 
a useful appendix to Semper’s c Animal Life.’ 
Animals and Therapeutics.§ — Prof. W. Marshall gives in his usual 
happy way an account of the old-fashioned uses of animals in medicine. 
Some of the modes of treatment have of late acquired a new interest in 
connection with the modern use of thyroid, pituitary, and other extracts. 
* Biol. Centralbl., xv. (1895) pp. 561-71. 
f Vierteljahrschr. Nat. Ges. Zurich, xl. (1895) pp. 159-201. 
X ‘ L’influence du milieu sur les animaux,’ Paris, 1894, 12mo, 176 pp. 
§ 4 Neueroffnetes, wundersames Arzenei-K'astlein darin allerlei griindliche Nach- 
richten wie es unsere Voreltern mit den Heilkraften der Tiere gehalten haben, zu 
finden sind,’ Leipzig, 1894, 8vo, 127 pp. 
