THE TROPICAL 
AGRICULTURIST. [June i, 1895. 
A Volume of this kind was very much needed, 
and it is a matter for congratulation that the work 
has' fallen into the most competent bands. There 
was nothing of the kind i i English Lefore, and 
the book will be of the greatest service to both 
teachers and students. It must be cl arly under- 
stoil that it is a strictly practical laboratory guide, 
which can only bo used by those who are willing 
to experiment for themselves The volume is iu 
no sense a treatise on physiology, and thus differs 
from its German predecessor. Detmter's "Pflmzeo- 
physiologisches Practicum. " which i3 to some extent 
a compromise between a practical guide and a 
theoretical text-book. The thoroughly practical char- 
acter of Stesscs. Darwin and Actons book seems 
to m a great merit; every word in it is of direct 
use to the experimental worker, and to him alone 
We cannot attempt to give anything like a summary 
of the contents of the work, which, in spite of its 
moderate bulk, covers a greU deal of ground. Thus 
in part 1. aloue, no less than 265 distinct experiments 
are described. Of course they vary very much in 
character, some being quite simple and elementary, 
while others are more of the nature of original 
research. It goes without saying that a large pro- 
portion of the experiments are of Mr. Darwin's own 
devis ng, and that nearly all have been practically 
test.d by the authors. Wherever this is not the 
case, the reader is told so; and if the experiment 
i>, from any cause, at all likely to fail, he is 
warned of the possible disappointment. The can lour 
with which the student is treated all thrcigh. is a 
very pleasant featre f the bo^k. 
The first chapter is on some of the conditions 
affecting the life of plants, and as the preseuce of 
oxygen is among the most important of these condi- 
tions, respiration is taken first. Besides the more 
usual experiment', inganims demonstrations of intra- 
molecular respiration, and of the excessive consump- 
tion of oxygon by germinating oily s eds, are given. 
In the secnl chapter assimilation takes the first 
place, and many beautiful experiments are described; 
including Gardiner's ihgeuio is modification of Sachs's 
iodine method, in which the sun is made t > print 
off, in starch, a copy of a potogriph, from a negative 
placed on the leaf. Au experiment proving that 
excess of carbon dioxide stops assimilation, is espec- 
ially interesting. When a second edition is called 
for, Mr. Blackmau's new and important experiments 
on the function of stomata will no doubt find a place. 
In the next chapter, which also concerned with 
nutrition, particularly good and complete directions 
are given for the management of water-cultures; 
these are qui'e the best we have met with, and will 
save the experiment r from many fai'ures. The use 
of Duckweed (Lemna) for demonstrating the effect 
of various food-solutions on growth, is, we believe, 
new, and is a very neit method. The same chapter- 
includes experiments on the nutrition of the carni- 
vorous plant, Sundew, a subject o ; which Mr. Darwin's 
investigations have become classical. 
The question of the moveraeut of water iu p'auts 
is still unsohed. The data of this problem, however, 
are very thoroughly taught, by meaus of the experi- 
ments described in the sections on the functions 
of roots, and on transpiration. The latter process is 
investigated, in the first instance, by meaus of the 
promoter, an instrument devised by Mr. Darwin and 
his pupil Mr. Phillips, in which the speed of the 
transpiration-current is measured by the rate of 
ascent of au air-bubble, which is drawn up a capillary 
glass-tube by a transpiring shoot connected with it, 
A particularly ingenious experiment is one in 
which the hygroscopic twisting and untwisting of an 
awn of the grass Stipa, is made use of a3 an index 
of transpiration. 
A chapter on physical and mechanical properties 
treats of such phemonena as imbibition, turgor, 
osmosis, and the tensions of tissues. It may be 
pointed out that in the description of Traube's 
artificial cells, copper sulphide is evidently a misprint, 
either for copper chloride, or sulphate (p. III). 
The next chapter is on gromtk, and conuiua, 
among inauy other things, full dir actions for th^ use 
of the various kinds of auxanoineter. 
The remaining chapt rs are coucerned w ;th curva- 
tures ( gootropism, heliotropisTi, traumatic cunature. 
<kc. ), and with other movements. S)ni3 of the 
most fascinating experiments come iu this pirt; we 
will only mention thosj on the decapitation of roots, 
au operation which, as Charles Dirwiu disc nvred 
prevents the root from perceiving the geotropic 
stimulus, though it does not hinder the curvature 
of the growing region which may have been induced 
by a preions stimulation. Attention is here called 
t) the brilliant experiments ol Prof. Pf.effer. »hich 
have denonstrated coucliieively that the tip of the 
root is alone sensitive to gravitation, thus finally 
confirming the co elusion drawn by Darwin from 
less decisive experiments. The announcement of this 
discovery by Prof. Pfeffer was one of the moat 
interesting incidents in the Biological Section at the 
Oxford mee.ing of the British Association. 
A self-recording method for studying the ele^p- 
movemeuts of leaves, strikes us as especially valuable. 
The second part of the book, on the chemistry 
of matabo'ism, is of quite a different character from 
part 1., and is evidently intended for students with 
an advanced chemical knowledge, who alone can 
make in'elligent use of it. The object aimed at is 
sufficiently explained in the opening paragraph: 
" The practical study of the transformations which 
plastic substances undergo in metabolism, is an 
application of organic chemistry: the immediate 
problem is generally to determine whether certuin 
Bubstanc-s are present or absent, and, if present, in 
what amounts in particu'ar tissues '' 
The mods of determination of all the import int 
organic bodies occurring in plants, such as protein, 
aur.des. oils, carbohydrates, tannis acids, and enzymes, 
is concisely explained. 
There are two appendices, the first of which gives 
examples of quantitative results obtaine 1 in actnat ex 
perimeuts in oHer to show the degree of accuracy 
which may fairly be expected; t e second is a list 
of reagents. Within the sho^t space of ninety email 
pages, which i3 all that the second part occupies, 
it is obviously imoossible to give full instruction in 
such a difficult a id complicated subject as the prac- 
tical physiological chemistry of plants. Those, how- 
ever, who are alrealy g>od chemists, will no donbt 
derive great help from the terse directions given here, 
especially as these are supplemented by abundant 
references to the more special literature*. 
The authors are much to be c mgratulated on their 
work, which fills a serious gap in the botanical 
literature of this country. We think it very desirable 
that a smaller edition of the bo->k should be published 
for use in schools, bearing somewhat the same relation 
to the present handbook as Prof. Bower's "Practical 
Botany for Be.'inners" bears to his larger manual 
on the same subject. It is most important, now that 
physiological bo'any is supposed to be taught in so 
many schools throughout the country, that it should 
really be taught in the only efficient way, namely 
by experiment, and that it should no longer be made 
a mere matter of " cramming, " as is now too often 
the case. A selec'im from the present book of the 
simplest and most fundamental experiments, such as 
could be performed with tolerable certainty of result 
in ordinary science-schools, would, we are sure, be 
of the greatest service to conscientious teachers, who 
desire to mike their scientific instruction a reality. 
D. H. S. 
— at. we. 
Season Repobts for Apbil. — In the Trincomalee 
district, of the Eastern Province, paddy and tobacco 
are favourably reported upon. In Uva. the young 
paddy plants show good promise, the spell of drought 
having at last terminated. Average prices : paddy 
per bushel, R2 ; rice per bushel. Bo ; Indiaucorn per 
bushel, Re. T25; kurakkan per bushel, Re. P50; salt 
per measure, emits 12|.— Gasette* 
