37 2 
NATURE 
[JUNE II, I914 
deepening of feeling. And if natural history is 
asked to give hints to the human edvcationist, 
one of them is this: ‘Youth should be spent in 
blunting (a term apt to be misunderstood?) every 
instinct, in awakening and_= stimulating every 
curiosity, in the gayest roving, in the wildest 
experiment. The supreme duty of youth is to try 
all things.” 
MANUALS OF BOTANY. 
(1) Pflanzenmikrochemie. Ein Hailfsbuch beim 
mikrochemischen Studium pflanzlicher Objekte. 
By Dr. O. Tunmann. Pp. xx+631. (Berlin: 
Gebriider Borntraeger, 1913). Price 18.50 
marks. 
(2) Researches on Irritability of Plants. By Prot. 
J. C. Bose. Pp. xxiv+376. (London: Long- 
mans, Green and Co., 1913.) Price 7s. 6d. net. 
(3) Plants and their Uses. An Introduction to 
Botany. . By BK. AL... Sargent. Pp: |x G20: 
(New York: Henry Holt and Co., 1913.) 
(r) OTANISTS who have not kept in touch 
with the more recent advances in the 
microchemistry of plants will be surprised at the 
size of this work with its 600 closely-printed pages. 
The book is divided into a general and a special 
part. In the first part we have, first, sixty pages 
dealing with methods of preparing and preserving 
material and with various other special methods 
such as filtering, centrifuging, sedimentation, 
micro-sublimation (a method of great value in 
many cases), clearing, swelling, bleaching, macer- 
ation, etc. In the second part the methods of 
recognising the various elements of the ordinary 
inorganic substances of the plant are considered, 
and later the various classes of organic substances 
are dealt with fully. The author, however, does 
not stop here, but in the last 200 pages passes in 
review the microscopical characters and_ the 
chemical nature of protoplasm, cell-wall, and cell- 
inclusions generally; this section includes details 
of fixing and of the staining reactions of the 
various cell elements. It will be seen that the 
author interprets his subject very broadly as, in 
fact, coextensive with botanical microtechnique. 
The need for such a book is very obvious since 
the last work covering such a field was very much 
smaller and was published in 1892. Dr. Tun- 
mann has made many contributions himself to the 
study of plant microchemistry, and no one could 
be better fitted to prepare such a work. 
The literature of the subject has been worked | 
up in a way which must have taken years to 
complete and nearly every page bristles with re- 
ferences; the work is, however, no mere compila- | 
tion, for the physiological aspects of the different | 
NO. 2328, VOL. 93] 
| substances are briefly dealt with and many methods 
critically discussed. Of course, it is impossible 
to read and criticise this book as a whole, but 
when tested in relation to a number of diverse 
substances, such as the microscopical recognition 
of potassium, of formaldehyde, of sugars, etc., it 
has proved to be thoroughly up-to-date. Botanists, 
plant biochemists, and those who have to deal with 
the recognition of vegetable tissues and drugs 
used in pharmacy are under a heavy debt of grati- 
tude to the author. The book should be on the 
shelves of every botanical, biochemical, and 
pharmaceutical library. 
(2) This volume is the fourth of the series of 
books in which Prof. Bose has applied the delicate 
methods of the physical laboratory to the study 
of the irritable responses of plants and animals. 
As his previous work has shown, the author looks 
upon the plant as a very peculiar machine of which 
the sole source of energy is that which plays upon 
it directly from without! Such views, however, 
should not blind plant physiologists, and animal 
physiologists interested in the neuro-muscular 
electrical response, to the solid value of many of 
the results obtained and to the usefulness of the 
ingenious and delicate apparatus devised by the 
author. His resonant recorder is a beautiful piece 
of apparatus in which the recording lever is made 
to vibrate to and fro and so to make only an 
intermittent contact with the recording surface ; 
the friction between the lever and blackened sur- 
face is thus enormously reduced. By means of 
this apparatus and of another ingenious instru- 
ment, the oscillating recorder, the delicate move- 
ments of the leaves of Mimosa and Biophytum 
have been recorded for the first time without dis- 
tortion, and so the latent period and the rate of 
transmission of a stimulus carefully measured. 
Very good reasons are given for the belief that 
in Mimosa an impulse cannot pass through dead 
tissues, in the manner commonly accepted, as a 
mere hydro-mechanical disturbance, but only 
through living protoplasm, the mode of trans- 
mission being essentially similar to that of a 
nervous impulse. 
There is much other work of importance, es- 
pecially in connection with electrical responses, 
and one is glad to note that startlingly unorthodox 
views are much rarer than in previous works. 
Prof. Bose, however, must be unaware of, or 
careless of, the prejudices of biologists or he 
| would not put forward, without the support of 
further experiments, the conclusion that in a bean 
leaf “‘on account of fatigue, the death point was 
lowered from the normal 60° C. to 37°C.” 
(3) This book is described as an introduction to 
botany. The plan of the work is based on the 
