366 
NATURE 
[JANUARY II, 1917 _ 
ORGANIC CHEMISTRY FOR AGRICUL- 
TURAL STUDENTS. 
Organic Agricultural Chemistry (The Chemistry 
of Plants and Animals). By Prof. J. S. Cham- 
berlain. Pp. xvii+319. (New York: The 
Macmillan Co.; London: Maemillan and Co., 
Lid), 1916:))  Pricéi7s/imer: 
HIS volume is intended to solve the difficult 
problem of providing a course in chemistry 
for students at agricultural colleges. By common 
consent the ideal plan is for the would-be agricul- 
tural chemist to go through the pure chemical 
course and take an honours degree. But many 
cannot do this; their training has to be carried 
out at the agricultural college, where chemistry 
as such is strictly subordinated to the matter in 
hand. 
Prof. Chamberlain deals with the problems by 
picking out those substances that the student will 
come across in his agricultural studies, and then 
connecting them together by building up the 
course round them. Necessarily this prevents dis- 
cussion of many problems of chemical interest ; 
constitutions have to be taken on trust without 
even an indication of the way in which they have 
been established. The course, too, is necessarily 
altered, and many old friends disappear: the 
ketones are not mentioned; even acetone is not 
described. 
But the book has to be judged by its suitability 
for the people for whom it was written, and from 
this point of view it is satisfactory. The ordinary 
simple substances are dealt with in sufficient detail, 
and the experiments are numerous enough to 
ensure that the student shall familiarise himself 
with them. Fats, sugars, starches, and proteins 
are discussed in a simple manner, and various in- 
teresting illustrations are given that show the 
bearing of chemistry on the problems of everyday 
experience. 
The first section of the book having dealt with 
organic substances, the second is devoted to 
physiology, both of plants and of animals. It is 
unfortunate that the lecturer in agricultural 
chemistry is almost always called upon to teach 
these subjects, for it is obvious that no man can 
do justice to physiology when he has to bring it 
in simply as an “extra.” Prof. Chamberlain has 
courageously introduced the chapters, and no 
doubt they will supply the teacher’s needs. But 
throughout one has the feeling that agricultural 
chemistry ought not to be extended to include 
physiology. 
The third section treats of crops, which 
undoubtedly belong to the subject. An account 
is given of the proximate and ultimate con- 
stituents of the ordinary crops, and of their value 
to both man and animals. The author classifies 
them on p. 150 as volatile and non-volatile, using 
“volatile”? to include starch, cellulose, protein, 
etc., and “non-volatile” for the ash constituents. 
It would have been better to retain the old terms 
“organic” and “mineral,” or something that does 
not involve calling cellulose a “volatile” sub- 
stance. 
NO. 2463, VOL. 98] 
Several omissions call for remedy. In a book 
of this kind the student may reasonably expect 
to find the answers to the questions that arise in 
everyday practice. What, for instance, is the 
constituent in cotton-seed cake that has such a 
“binding ” effect on cattle? or the substance in 
young grass that makes them scour? Why is. 
May grass better than October grass? Why have 
mangolds to be stored some months before they — 
can safely be used? These are the kind of ques- 
tions about crops that are perpetually before the 
agricultural instructor in this country, and a 
similar variety of questions must be put by in- 
quisitive farmers in the States; they represent 
the kind of problem that the text-book writer 
ought to face. 
The book has several new features which seem 
decidedly useful. No space is lost in giving” 
details of analytical methods which, as the author 
truly observes, can be got out of the analytical 
text-books. The detailed study of animal nutri- 
tion is taken before that of plants—a course which, 
in the author’s experience, gives the student a 
clearer conception of the biochemical changes 
involved, and at the same time emphasises both 
the differences between plants and animals and 
their fundamental similarity. 
No references to original papers are given, but 
there are references to larger text-books, so that 
the student seeking further information will know 
where to find it. 
The book is, we believe, the only one of its 
kind. The well-known volume by Haas and Hilf 
was written from the general biochemical point of — 
view. Prof. Chamberlain is, so far as we know, 
the only recent chemist who has written organic 
chemistry for agricultural students. E. J. R. 
COLOUR. 
Color and its Applications. By M. Luckiesh. 
Pp. xii+357- (London: Constable and Co., 
Ltd., 1915.) Price 16s. net. 
as is always difficult, if not impossible, to 
separate the principles of a science from the 
applications of them, and the author has, perhaps 
wisely, not attempted to do so. On the other 
hand, while a student may be able to master the 
principles so far as they have been made clear, 
he can never hope to become practically acquainted 
with the innumerable applications of such a sub- 
ject as colour. Therefore, we have here a very 
good account of the fundamentals, and a similarly 
good account of some of the applications, while 
other of the latter are treated in so limited 
a manner that it can scarcely be claimed that they 
are fairly presented. With these few exceptions,, 
which indeed the author from his preface evi- 
dently appreciates, we have a very useful general 
treatise on colour which includes 130 well-selected 
diagrams, curves, and tables, so that for very 
many purposes the book will be found sufficient 
in itself. But at the end of every section refer- 
ences are given to other text-books and to original 
papers to facilitate a more extended study. 
About three-fifths of the volume is devoted to 
