ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 
311 
increased surface tension is internal ; it is due to the nuclear substance, 
for which the exhausted protoplasm now exhibits chemotropism. A 
fragment without a nucleus will flow into one which has intact nuclear 
material. 
Fibrillar structure, e. g. of muscle, is a differentiation which secures 
a motor effect in a definite direction. Here the conditions of surface- 
tension are obviously more complex than in the Rliizopod ; moreover, 
the muscle has a definite tissue environment. Yet in regard to the 
stalk of Yorticellidre the author finds it possible, with no little inge- 
nuity, to make his theory hold good. Into a record of Yerworn’s still 
more ingenious interpretation of the contraction of striped muscle we 
refrain from entering. 
The Living Organism.* — Sig. F. Ardissone has published a corrected 
edition of his essay on the living organism, its essence and origin. As 
previously noticed, the essay chiefly deals with familiar philosophical 
questions, such as those of materialism. 
Plankton.f — Prof. E. Haeckel gives an analysis of a Plankton collec- 
tion from the Atlantic, Indian, and S. Pacific oceans. The method of 
analysis consisted in estimating the components in tenths and percentages 
of volume. The results are discussed under four heads : — “ monotones, 
praevalentes, polymiktes, and pantomiktes plankton.” In the first, at least 
nine-tenths of the volume consists of similar or identical forms, e. g. 
Copepods, or Radiolaria. In the second, at least a half consists of similar 
or identical forms ; in the third, no one kind of animal forms over 49 
per cent, of the volume ; in the fourth, there is a heterogeneous mixture, 
each sample being a miniature of the general plankton-composition. 
Biological Nomenclature. — The American Association for the 
Advancement of Science has issued a circular containing the recommen- 
dations of a special committee, which were unanimously adopted at the 
Rochester meeting. They think it is necessary to arrive at some 
agreement as to the underlying principles that should govern Biological 
Terminology. In an “ authoritative glossary ” the Latin form should be 
given as the major heading, and the more common vernacular forms 
should also be given. They strongly recommend the use of mononyms 
as against descriptive phrases, etymological correctness, and the forma- 
tion of paronyms — e. g. Biology is the English paronym of Bio- 
logia. 
B. INVERTEBRATA. 
Influence of Light on Development of Animals.^ — M. E. Yung 
finds an exception to the rule that green light is unfavourable to the 
development of animals ; this is afforded by some symbiotic forms, 
the green Planarians, and the green Hydras, for the former do not do 
better with violet than green light, and the latter grow more quickly in 
red than wh.te light. 
* ‘ L’Organismo vivente considerato nella sua essenza e nella sua origine,’ 2nd 
ed., Varese, 1893, 25 pp. 
f Jenaische Zeitschr. f. Naturwiss., xxvii. (1893) pp. 559-66. 
t Comptes Rendus, cxv. (1892) pp. 620-1. 
