1910] CURRENT LITERATURE 151 
and the fermentable substances. To BERTRAND we owe the introduction into 
science of the term oxidase. The adoption of this general term was based upon 
the discovery and characteristics of laccase and tyrosinase. The chapter con- 
cludes with a classification of oxidases and special reference to the sources, prepara- 
tion, and characteristics of laccase, tyrosinase, aldehydase, and the purin oxidases. 
The third chapter is devoted to the peroxidases and catalases. The weight 
of opinion is inclined to the conception that peroxidases are substances capable 
of forming unstable peroxids from hydrogen peroxid, by double decomposition 
or by combining directly with the hydrogen peroxid to form unstable holoxid 
(TRAUBE) derivatives, possessing greater powers of oxidation than hydrogen 
peroxid. - 
Bacn and CHopar’s conception of an oxidase consisting of a mixture of 
peroxidases and peroxid-forming substances (oxygenases) would make the 
peroxidases the more important agents in plant and animal oxidations, and would 
relegate the oxidases to an insignificant position in such oxidations, if indeed 
they function as enzymes at all. In the author’s opinion the objections which 
have been recently urged against the true enzymatic nature of oxidases are well 
taken. 
A considerable amount of evidence is brought together to show the importance 
of iron, copper, and manganese as coenzymes to oxidizing ferments. According 
to BERTRAND, manganese is the really active element of the oxidases, so far as 
the activation and transfer of oxygen is concerned. EvLer and Botin have 
found that laccase has no action on hydroquinone in the absence of manganous 
salts, and therefore they suggest that laccase owes its activity to the presence of 
such salts. In this connection it is interesting to note that in a paper by BacH,* 
more recent than the above monograph, he claims to have obtained a tyrosinase 
which will oxidize tyrosin to the red stage and is free from both iron and man- 
ganese. He concludes, therefore, that manganese and iron salts are in no way 
necessary for oxidase activity. One of the most valuable features of the mono- 
graph is the comprehensive list of references to the literature——-CHARLES O 
APPLEMAN, : 
Colloidal chemistry 
The newer plant physiology should welcome the appearance of FREUNDLICH’S 
books on colloidal chemistry, or capillary chemistry, as he terms it. This is the 
first attempt to bring together our knowledge of this youngest and most difficult 
branch of physical chemistry. It puts the physiologist immediately in touch 
with the present status and most important literature of a subject which seems 
destined to play at least as important a rdle in the study of vital phenomena as 
*Bacu, A,, Zur Theorie der Oxidasewirkung. Ber. Deutsch. Chem. Gesell. 
43:362. 1910. : 
3 FREUNDLICH, HERBERT, Kapillarchemie, eine Darstellung der Chemie der 
ide und verwandter Gebiete. Svo. pp. viii+so1. figs. 75. Leipzig. 1909. 
