O74 
its relation toenzymes. Chapters I. to IX. treat 
of enzymes acting upon various carbohydrates ; 
they comprise diastase, maltase, inulase, cytase 
and others. Chapter X. considers the glucos- 
side-splitting enzymes, as emulsin, myrosin, 
rhamnase and others. Chapters XI., XII. and 
XIII. treat of proteolytic enzymes, as pepsin, 
trypsin, papain, bromelin, etc. Chapter XIV. 
describes the fat-splitting enzymes, and the fol- 
lowing three chapters the clotting enzymes, 
rennet, thrombase and pectase. Then follows 
urease and hystozym. Chapter XIX. is devoted 
to the oxidizing enzymes, and Chapter XX. to 
the alcoholic fermentation. Chapter XXI. 
treats of the fermentative power of protoplasm, 
Chapter XXII. of the secretion of enzymes, 
Chapter XXIII. of the constitution of enzymes, 
and Chapter XXIV. of the theories of fermenta- 
tion. 
In the preface and first chapter the author 
defines his own position in regard to views on 
fermentation. He lays stress on the relations 
between ‘‘fermentation in the broad sense and 
the general metabolic phenomena of living 
organisms.’’ Recent discoveries ‘‘ have shown 
more and more plainly what a prominent 
part is played by enzymes in intracellular 
metabolism, till it has become clear that the 
distinction drawn between organized and un- 
organized ferments is based upon an incom- 
plete acquaintance with the metabolic processes 
in both higher and lower organisms, and must 
now be abandoned entirely in the light of 
fuller knowledge.’’ He defines consequently 
fermentation to be the ‘‘decomposition of com- 
plex organic material into substances of simpler 
composition by the agency either of protoplasm 
itself or of a secretion prepared by it.”’ 
While this general view hardly requires any 
further comment, grave doubts may be ex- 
pressed as to the correctness of his general 
view on‘the characteristics of protoplasm. 
The author adopts the views of Pfluger and 
Detmer, and believes in its ‘‘ continually un- 
dergoing decomposition and reconstruction.”’ 
This decomposition can, however, continue for 
only a short time, as otherwise death would re- 
sult before reconstruction could take place. 
To explain the principles of life as a perpetual 
destruction and reconstruction of protoplasm 
SCIENCE. 
[N.S. Vou. X. No. 246. 
shows very erroneous conceptions. The ma- 
terial destroyed in the process of life con- 
sists of 99 per cent. of carbohydrates, fats and 
passive proteids of the food, but not of the 
living matter itself. The general descriptions in 
Green’s book of enzymes and their physiolog- 
ical relations correspond to the relations of 
the plant physiologist. We find in Green’s 
book excellent paragraphs on diastase of secre- 
tion and diastase of translocation ; on the con- 
dition of secretion of diastase and the con- 
dition of the action of diastase ; on cellulose, 
dissolving enzymes, and on vegetable trypsins. 
But wherever the progress of modern chemistry 
comes into play the physiological chemist will 
hardly be satisfied. The author ignores the 
principle of chemical lability of the proteids of 
living matter and in enzymes, by which prop- 
erty heat can be converted into mechanical 
energy. 
The author has overlooked further certain 
points in recent chemical literature ; otherwise 
he would not have mentioned (p. 168) antipep- 
tone as a chemical substance. Recent investi- 
gations have placed beyond doubt the fact that 
the so-called anti-peptone is no peptone at all, 
but essentially a mixture of several bases, viz., 
arginin, lysin, histidin. 
Further, Green mentions on page 174 the 
artificial production of an albumin from pep- 
tone by acetic anhydride, although it was 
shown several years ago thatin this way merely 
an acetyl peptone, but no true albumin, is ob- 
tained. v 
In regard to the preparation of diastase Green 
describes several methods, but not without 
making various errors. In the first place he 
callsthe method which makes use of basic ace- 
tate of lead for the isolation of enzyme Loew’s 
method, while it was Wurtz who applied this 
method first and with great success in the isola- 
tion and purification of another enzyme papain.* 
In the second place Green calls this method 
untrustworthy, although he did not control it 
by a single experiment, but merely relied upon 
the judgment of a young chemist, who in the 
first investigation he had ever published failed 
to obtain a powerful diastase. This was, how- 
ever, due to the fact that he had not yet ac- 
* Comptes Rendus, 90, 1379 and 91, 787 
