198 
how extremely sensitive the enzymes are to antiseptic 
and toxic substances ; we have not heard of magnetism 
or electricity being affected in a like manner. But 
whatever the truth may be, it cannot but be admitted 
that our present knowledge as to what diastatic action 
really may be is incomplete and vague in the extreme. 
Possibly the elucidation of many of the difficulties will 
follow the preparation of a pure enzyme. 
One difficulty encountered in studying the enzymes is 
the multitude of names which a single enzyme may 
possess, ¢.g. on p. 51 we are told that sucrase is variously 
called “glucose ferment, cytozymase, zymase and in- 
vertin.” The chief reason for this diversity of names is 
that different investigators, having obtained from different 
sources a diastase capable of transforming cane sugar 
into invert sugar, have often been under the impression 
that they have come across a new diastase and have there- 
fore invented a name for it. 
Chapters v. and vi. deal with sucrase from a theoretical 
aspect, and chapter vii., on the fermentation of molasses, 
introduces us to the technical portion of the work. Al- 
though sucrase is not prepared commercially, it plays a 
very important part in fermentation, especially in the 
manufacture of alcohol from molasses. 
Dr. Effront has evidently studied the technical part of 
the question with the same care which he has devoted to 
the scientific side. As a consequence the chapters on the 
technology of the enzymes should be very valuable to 
those interested in this branch of the subject. The 
space at our disposal forbids us to more than _ briefly 
notice some of the important applications of enzymic 
fermentation. There is an interesting chapter on 
“Panary Fermentation,” and here one cannot but be 
struck by the fact that although the art of bread-making 
is one of great antiquity, yet we know very little as to 
what really does take place in the process of bread- 
making. 
Chapter xviii. deals with the industrial application of 
“maltase” (the ferment of maize, which also occurs in 
small quantities in yeast) and the manufacture of glucose. 
Chapter xxi. should be of great interest to chemists, as 
it treats of the ‘“‘ Ferments of Glycerides and Glucosides.” 
Among the various enzymes here discussed, we notice 
“Jipase,” the active principle of the pancreatic juice, 
“emulsin,” which occurs in almonds, and “erythrozyme,” 
the ferment contained in the madder root. This chapter 
might with advantage have been extended, but, unfortu- 
nately, our knowledge of these very interesting substances 
is not yet very far advanced. 
In conclusion, we must not forget the translator, Mr. 
Samuel C. Prescott, who has carried out his labours in a 
most satisfactory manner. F. MOLLWO PERKIN. 
OUR BOOK SHELF. 
Astronomischer Jahresbericht. By Walter F. Wisli- 
cenus. Band iii. Pp. xxxi + 671. (Berlin: Georg 
Reimer, 1902.) 
THE value of this work to astronomers and others inter- 
ested in astronomical matters is now so well known, in 
spite of this being only its third appearance, that the 
present issue will be warmly welcomed. In the compila- 
tion of such an undertaking as this, Dr. Wislicenus and 
his co-workers are to be heartily congratulated, for they 
NO. 1704, VOL. 66] 
NATURE ' 
[JuNE 26, 1902 
have brought together a very great number of most. 
useful references and excellent brief extracts of all the 
more important publications of the past year. The 
volume now contains 671 pages, and the compiler informs 
us that this will probably be about its normal size. The 
second volume contained 552 references more than the 
first one, and the one before us shows an excess over 
the second by 193 references. This latter excess was 
chiefly due to the great number of papers on Nova 
Persei, which required 228 references alone. In future, 
to keep down the number of such references, the com- 
piler proposes to include under one reference all those 
publications which appear during a year under the same 
heading and by the same author. This seems a very 
rational suggestion. 
It may be mentioned that references are not only given 
to all the original publications, but also to all transla- 
tions of such publications and astronomical articles 
which have appeared in various quarters. Thus, to take 
a case in point, we find that the communication by 
Dr. J. Hartmann to the Sz¢z. der Kgl. preuss. Akademie 
der Wiss. zu Berlin on “ The movement of the Pole Star 
in the line of sight” was translated into English in the 
Astrophysical Journal, and was noticed in Sirius, Die 
Natur, Astronomische Rundschau, Das Weltall and the 
Revue Scientifique, their respective references being 
added in each case. 
The book concludes with a capital index of names and 
brief tables of errata to the second and present volume. 
In addition to those mentioned in the present volume, 
which, by the way, are remarkably few in number con- 
sidering the work involved, may be added “ Norman ” 
instead of “ Normann” in references Nos. 1454 and 
2131, and ‘‘nachste Maximum” instead of ‘“‘jetzige 
Minimum” in reference number 1510. 
In conclusion, it is hardly necessary to point out that 
no astronomical observatory or similar institution should 
be without this volume, which embodies in it all that 
relates to the recent progress of astronomical science, 
not only in this country, but over the whole world. 
That the work has in its third year become so complete 
is due to the untiring labours of Dr. Wislicenus and his 
co-compilers, and it is hoped that such may in the future 
be lightened by the endeavour of all interested in such 
a useful undertaking to remember to send them separate 
copies, reprints, &c., of published papers. 
W. J. S. LOCKYER. 
Elements of Metaphysics. By J. S. Mackenzie. Pp. 
xv + 172. (London: Macmillan and Co., Ltd., 1902.) 
Price 4s. 6d. 
PROF. MACKENZIE is to be congratulated on having 
produced an exceedingly useful little book of a kind which 
has no precise counterpart in our current philosophical 
literature. Within the compass of less than two hundred 
small pages he deals very suggestively with the nature 
of the metaphysical problems, the methods of meta- 
physical science and its relation to the rest of our 
theoretical and practical interests, science in general, art, 
ethics, and religion. The aim of his discussion is not so 
much’ to indicate conclusions as to lead his reader to: 
comprehend the nature of the problems to be solved and 
the methods of solution which are at our command. 
Hence the beginner in philosophy could hardly have a 
better introduction to what is, after all, the main business 
of philosophy, the practice of thinking intelligently for 
himself on the ultimate problems of knowledge. So far 
as the author’s own conclusions in philosophy are put 
forward, they indicate a rare catholicity of view with a 
certain bias in favour of the line of thought, represented 
by Aristotle and Hegel among the great names of meta- 
physics, which insists upon development as the key to 
the understanding of the forms of existence. As might 
be expected’ from his choice of philosophical masters, 
