JUNE 24, 1915] 
NATURE 
449 

must be explained.” Chapters i.-vii. are con- 
cerned with various aspects of case-hardening pro- 
cesses, and these are followed by others dealing 
with methods of testing, automobile steels, harden- 
ing and tempering, and finally surface hardening 
without cementation. No attempt is made to 
separate the subject into practical and theoretical 
divisions, and the author’s treatment presupposes 
an elementary knowledge of metallography on the 
part of his readers. 
In a book of this kind it is gratifying to find 
the following opinion (p. 77): ‘The most helpful 
of all generalisations in metallurgy is the one 
based on observations made with the pyrometer 
and confirmed by the microscope, known as the 
equilibrium diagram.” Mr. Brearley is to be 
congratulated on the production of a book that 
was well worth writing, and one which should 
certainly be of use to those for whom it is in- 
tended. It will repay studying, moreover, by 
others than case-hardeners. 
The Principles of Fruit-Growing. By L. H. 
Bailey. Twentieth Edition. Pp. xiv+432 
(New York: The Macmillan Co., London 
Macmillan’ and Co., Ltd} rors.) Price 
7S. Odemnet 
Tuts book has in its different editions been used 
for nearly eighteen years as a standard text-book 
on commercial fruit-growing, in the Agricultural 
and Horticultural Colleges of the U.S.A., Canada, 
and England. 
For the present edition the work has been 
largely re-written; it deals with important subjects, | 
such as the choice of locality and site; the setting 
out of orchards; the principles of vegetable 
physiology involved in the cultivation, pruning 
and thinning of the fruit, andso on. The question 
of manuring of orchards, based on experiments 
at the American Experiment Stations, gives clear 
general reasons for the effect or non-effect of the 
fertiliser. The phenomenon of self-sterility of 
varieties and the advantage of cross-pollination 
are discussed. Examples of score cards dealing 
with the growth and character of the tree as well 
as the fruit show that this is a valuable method 
for comparison of varieties; an example of a 
work sheet of an orchard, together with cost and 
return, show what may be advantageously learnt 
from keeping such a record. Cover crops and pro- 
tection from frost by orchard heating are 
described; control of insect pests and fungoid 
diseases, and the choice of pumps and nozzles, are 
well treated; harvesting, packing, and fruit stor- 
age houses, also special points of interest such as 
the origin of varieties, are discussed. 
The book is one to interest any English apple 
grower (it is the apple that is chiefly dealt with) ; 
it presents new aspects of things different from 
NO. 2382, VOL. 95| 

those we are accustomed to see in current English 
fruit-growing literature. : 
The application of principles may need slight 
modification in this country as the work is in 
the first case written for North America; the main 
general principles, however, hold good the world 
over. Cecit H. Hooper. 
Infant Mortality. By Dr. H. T. Ashby. Pp. 
x+229. (Cambridge: At the University Press, 
1915.) Price 10s. 6d. net. 
THE appearance of Dr. Ashby’s book is very well 
timed, for in these days of human wastage it 
behoves a nation to conserve its resources. It 
is true that in recent years there has been a 
slight drop in infant mortality, but it is still dis- 
gracefully high, and is largely counterbalanced 
by a fall in the birth-rate. The word disgraceful 
is the correct one, because the vast majority of 
deaths are due to preventable causes, of which 
the most important is diarrhoea due to bad feeding 
and especially to bad and _ infected milk. 
Dr. Ashby shows that much may be done by 
the proper instruction of the mothers, but by far 
the greatest responsibility falls on public bodies 
and the Government, for it is only they who can 
deal with the larger questions of hygienic pre- 
cautions, such as regulations of cleanliness in 
food depots, and the prevention of fly-borne 
disease; the call for proper regulation of the 
milk traffic is an urgent one; the provision of 
shells is important, but the provision of a healthy 
race to make and use them is even more pressing. 
We trust that useful books such as the one under 
consideration may bear fruit in the proper 
quarters. Wie ID Jel. 
St. Bartholomew's Hospital in Peace and War. 
The Rede Lecture, 1915. By Dr. Norman 
Moore. Pp. 56 (Cambridge: At the University 
Pressy 1Qns,)| mu biice 25a met. 
We welcome the publication of this Rede lecture 
delivered on May 6, 1915, in the Senate House, 
Cambridge, by Dr. Norman Moore. Such a 
charmingly written history of a great hospital will 
appeal to a wide circle of readers. As Dr. Moore 
says, the history shows “how in a free country 
such as ours, where everything is not dominated 
by Government, an ancient institution like 
St. Bartholomew’s Hospital, whether in peace or 
war, lives with the nation and is in touch with 
the national life in every period.” 
Educative Geography. A Note-book for Teachers. 
By J. L. Haddon. Pp. 76 (London: G. W. 
Bacon and Co., Ltd., 1915.) Price 1s. net. 
Ir is to be hoped that this little book may secure 
a wide circulation among teachers of geography in 
elementary schools and the junior classes of 
secondary schools. It should convince all who 
read it that lessons in geography become both 
more valuable and interesting when they include 
simple practical exercises to be worked by the 
children themselves, and that the provision of such 
work is neither expensive nor unduly troublesome. 
