34 
Some Aspects of the Algce. 
In A and B the enzyme is limiting; in C the maximum of pur- 
purogalline obtainable from 1 grm. of pyrogallol is already reached 
and this limits C, D and E : H proves this by showing that with 
increase of pyrogallol more purpurogalline is obtained. In F and 
G the hydrogen dioxide is limiting. 
It follows from this table that when OScc. of hydrogen per¬ 
oxide reacts with 1 grm. of pyrogallol in presence of -08 of enzyme 
extract, neither of the three is in excess, but all are just equivalent. 
From the various investigations recounted in this article we 
may fairly well conclude that, though the process of enzyme for¬ 
mation is yet obscure, the quantitative activity of existing enzymes 
and metabolic changes in the living cell must be governed by simple 
physico-chemical principles. 
SOME GENERAL ASPECTS OF THE ALGAL 
Morphologic und Biologic der Algen von Dr. Friedrich Oltmanns. 
Zweiter Band, Allgemeiner Teil. Pp. vi. and 443, 3 Plates and 150 
figures in the text. Jena, Gustav Fischer, 1905. 
ITH the publication of the second (general) part, 1 Professor 
Oltmanns’ great Hand-book of the Algre is completed. 
The system pursued in the present volume is to take various topics 
separately and to treat them generally and comparatively with 
regard to the Algse as a whole. The volume is divided into eleven 
chapters and each of these is devoted to one of these topics, which 
are as follows: System of the Algae, Development of Reproductive 
Organs, the Algal Cell, Nutrition, Conditions of Life, Periods of 
Vegetation, Phenomena of Irritability, Polymorphism, Alternation 
of Generations, Adaptations, Methods of Investigation. It will be 
seen that this scheme includes a great many, though by no means 
all, of the general points of view from which the Algae can be 
considered. Certain topics which might with advantage have been 
included at once suggest themselves, for instance the Phylogenetic 
Relation of the Algte to the rest of the Vegetable, and to the 
Animal Kingdom, the Place of the Alga; in the Economy of Nature, 
the Tissue Systems of the Alga; considered both morphologically 
and physiologically. But it may be admitted that it is unreasonable 
1 The first (special) part of this work was reviewed in the New 
Phytologist, Vol. IV., p. 85. 
