the five volumes will provide a systematic record of 
various lines of research, mainly physiological, which 
have been the subjects of investigation in the Botanical 
Institute of Brussels. 
The nature of the alkaloids found in plants and the 
methods of localising them is one of these subjects, and 
in the present volume there are two papers dealing with 
those bodies, the one by the late M. George Clautriau, on 
“The Nature and Significance of Alkaloids in Plants,” 
the other by E. Vanderlinden, treating of alkaloids in the 
Ranunculacez. A considerable part of Clautriau’s paper 
is historical, the present research being confined to 
caffeine obtained from coffee and tea plants. Having 
previously studied the alkaloids in various other plants, 
he is well qualified to summarise our present knowledge 
of them. Although alkaloids have only been located in 
a limited number of plants, Clautriau considers that they 
are probably formed in all plants, but not always in suf- 
ficient quantity to be stored up. Alkaloids derived from 
purine bases are found throughout the whole range of 
plants, while those derived from a pyridine base are con- 
fined almost exclusively to Angiosperms. Definite micro- 
chemical tests for alkaloids are wanting ; thus Clautriau 
was unable to obtain any which would enable him to 
detect caffeine zz s¢¢u. He concludes that alkaloids are 
decomposition products formed in the breaking down of 
proteids ; that they can be worked up again, but this 
requires a considerable expenditure of energy, and that 
generally their function is to protect the plant. Vander- 
linden’s results are quite in harmony with Clautriau’s 
views. He finds that the amount of alkaloid present in 
a plant is liable to fluctuations, these depending upon the 
phase of vegetation and the nature of the soil. Curiously, 
Ranunculus and Clematis, two genera weli known to 
possess toxic properties, yield no alkaloid. 
In a second paper, Clautriau describes his experiments 
on pitcher-plants, some of which were performed on 
plants in their natural habitat in Java, others after his 
return to Brussels. Vines, who has reinvestigated the 
subject on the strength of Clautriau’s results, does not 
confirm them, but decides that the ferment is tryptic, not 
peptic. 
In the course of his experiments on the permeability 
of protoplasm to liquids at different temperatures, van 
Rysselburgh disproves the view held by Schwendener 
and others that protoplasm is not permeable to water at 
o° C. ; in fact, he finds that it is permeable to potassium 
nitrate, urea, methylene-blue, &c., at the same tempera- 
ture. Another important observation was made that the 
sap in a cell if isotonic with a certain solution at any 
temperature will be isotonic with it for all temperatures. 
M. Jean Massart advances some decidedly unconven- 
tional ideas on the phylogeny of the lower organisms, 
which presumably have originated during his investigation 
of the protoplasm of the Schizophyta. His deductions 
as to the nature of the central body in the Schizophyceze 
and the stainable bodies in Bacteria are somewhat con- 
vincing, but at present many problems of the nucleus 
seem to be beyond our powers of solution. The last few 
pages of the publication are devoted to the description of 
a gigantic Bacterium, Spiril/um colossus, obtained by 
Prof. Errera from an ancient moat. 
NO. 1703, VOL. 66] 
NATURE 
[JUNE 19, 1902 
OUR BOOK SHELF. 
Dynamos, Alternators and Transformers. By Gisbert 
Kapp. Translated from the third German edition by 
H. H. Simmons, A.M.I.E.E. Pp. v + 503. (London: 
Biggs and Co.) Price tos. 6d. e 
Etude Pratique sur les Différents Syst’mes d’Eclairage. 
By J. Defays and H. Pittet. Pp. 168. (Paris: Gauthier- 
Villars, n.d.) Price fr. 3. 
Mr. Kapp’s book has passed through a somewhat curious 
development. Originally written in English, it first 
appeared in German as a translation; subsequently 
Mr. Kapp revised, and to a large extent re-wrote, the 
German translation, the revised book appearing as the 
third German edition in 1899. It is this work which has 
now been translated by Mr. Simmons. The general 
merits of the book are probably known to most electrical 
engineers ; those who are only familiar with the earlier 
English edition will find much that is new and valuable 
in the one now before us. After some opening chapters 
on the electric and magnetic theory underlying the 
design of dynamos, the winding of armatures is con- 
sidered in detail in a couple of chapters well illustrated 
by diagrams. The next chapter deals with field magnets, 
after which armature reaction, commutation and sparkless 
collection are considered at some length. Some typical 
examples of direct-current machines are described, but 
at no great length, as this ground has already been 
covered by Mr. Kapp in his “Dynamo Construction : 
Electrical and Mechanical.” The remainder of the book 
deals in a similar manner with alternators, synchronous 
and asynchronous motors, and rotary converters. 
Graphical methods are employed in this part to a con- 
siderable extent ; the mathematical treatment throughout 
the book is clear and concise, a certain familiarity with 
the differential and integral calculus being assumed in 
the reader: Asa whole the work forms a most valuable 
text-book for the student of this branch of electrical 
engineering. 
It will be noticed that the book does not deal at all 
with transformers ; this is because a separate work on 
this subject has been published by the author, a fact 
which is stated in the preface. Yet in spite of this, the 
title as it appears on the cover and page headings 
is “Dynamos, Alternators and Transformers,” which is, 
to say the least, misleading. On the title-page a different, 
and more accurate, name is given to the book. This 
defect is to be regretted, as it mars an otherwise excellent 
work. 
MM. Defays and Pittet’s volume cannot fail to prove 
attractive to those who are interested in the problems of 
artificial lighting. The authors have aimed at providing 
a practical guide to those who are called upon to select, 
as, for example, for lighting a factory, a suitable system of 
illumination. Naturally, in such a case, the question of 
relative cost is of prime importance ; the authors have, 
however, rightly abstained from dwelling too strongly on 
this point, as not only is the price so largely a question of 
locality, but it is often very difficult, if not impossible, to 
decide what is the monetary equivalent of the advantages 
which one illuminant possesses over another. The whole 
subject of artificial illumination is first dealt with in a 
general manner, the considerations of importance in 
relation to different conditions of use being pointed out. 
After this, separate chapters are devoted to a detailed 
examination of lighting by gas, acetylene, oil, alcohol 
and electricity. The principles underlying each system 
are expounded clearly and not too technically, and its 
security, healthiness and efficiency are discussed. From 
the hygienic point of view there can be no question as to 
the superiority of electric light; it is also more con- 
venient, and probably safer, than any other method ; but 
unfortunately it is considerably dearer, unless regarded 
from the enlightened standpoint which takes into account 
