Marcu 3, 1923] 

NATURE 
283 

considered generalisation, or for assuming the division 
of the Indiar races into a series of water-tight com- 
partments, a view contradicted by the whole course 
of Indian history. 
Among the elements which contribute to the 
formation of the Naga group of tribes must now be 
recognised the Negrito, because Mr. Hutton has 
detected among them examples of a type “with a 
decidedly dark-brown skin and fuzzy hair.” But it 
is to the Mon-Khmer races, deriving their origin 
ultimately from China and later from Burma, that 

we must look for the main constituents of the Naga 
Fic. 2.—A medicine man (Aatsen) in a fit. 
From ‘‘ The Lhota Nagas.” 
type. Mr. Hutton is possibly pushing the evidence a | 
little too far when he suggests a comparison between | 
a form of spear with ornamental barbs curving outwards 
from the shaft, a peculiar dao knife, and a shouldered 
hoe, with similar weapons and implements used by the 
Igorots of the Philippine Islands, as proving the common 
origin of these races. The general conclusion is quite 
acceptable, but it will need much further exploration 
to bring to light that amount of material by which 
so wide a generalisation can be established. But Mr. 
Hutton, who writes in a scholarly way and without 
any trace of dogmatism, is clearly working on scientific 
lines, and his admirable introduction throws much- 
needed light on the connexion of the races of eastern 
India with those of the Malay Peninsula and the islands ) 
NO. 2783, VOL. I11] 


farther east. It thus marks a decided advance towards 
the settlement of some of the most urgent problems 
of Indian ethnology. 
Mr. Mills’s work is an excellent example of field-work 
in ethnology, and it only remains “to say that 
monograph is furnished with a fine series of photo- 
graphs, maps, and an admirable index compiled by 
Lieut.-Col. J. Shakespear. 
his 

Our Bookshelf. 
An Introduction to the Chemistry of Plant Pro- 
ducts. By Dr. Paul Haas and T. G. Hill. 
Vol. 2: Metabolic Processes. Pp. viii+rgo. 
(London: Longmans, Green and Co., 1922.) 
7s. 6d. net. 
THE first volume of this work is already well 
known to students of plant physiology ; first 
issued in 1912, it is already in its third edition. 
In this third. edition the more physiological 
problems were left for treatment in this second 
volume, which is in effect a completely new 
book. In the brief preface the authors describe 
their choice between the alternative methods 
of treatment, and every student will be grateful 
for their courageous decision to attempt a con- 
nected account of the present state of our know- 
ledge rather than an encyclopedic digest of the 
literature. The result is a book much more 
open to criticism but infinitely more valuable. 
After a brief introductory section, devoted 
mainly to modern methods of measuring and 
expressing hydrion concentration, the synthetic 
metabolism of fats, carbohydrates and proteins 
is briefly considered, and two long chapters 
dealing respectiv ely with respiration and growth 
conclude a short but exceedingly suggestive 
volume. 
In the reviewer’s opinion, the authors have 
done a great service to botany by their clear, 
concise and eminently readable treatment of their 
subject. The brevity of the section devoted to 
fats probably adequately reflects our ignorance 
of their metabolism in the plant, though one would 
have liked to see reference to the recent investiga- 
tions of Neuberg and his collaborators. The section 
on photosynthesis forms an admirable complement to 
the monograph upon carbon assimilation by Jorgensen 
and Stiles, which considers the same problems from a 
more physical point of view. 
The treatment of protein metabolism is somewhat 
scanty, again a correct reflection of our ignorance, but 
an introduction to the recent work upon the relation of 
hydrion concentration to the chemical and physical 
behaviour of the amphoteric protein’ would have been 
very valuable for the English reader. The emphasis 
given to the dehydrase mechanism i in the treatment of 
respiration seems to the reviewer entirely sound ; until 
oxidase mechanisms can be proved more effective upon 
sugars, their significance as a general respiratory 
mechanism must remain under suspicion. The chapter 
