478 
NATURE 
| JuLy I, 1915 

dry weather flow of sewage is, perhaps, a usual 
capacity provided’’), affords such uncertain 
guidance upon important details of works design. 
Neither practical nor scientific value can be at- 
tached to Table XV, “Showing the dimensions of 
several septic tanks in use in England,” or to 
the bald statement that circular tanks of the 
Dortmund type are in use, as septic tanks, in 
the absence of comment as to the suitability of 
the design to the object in view. The comparison 
between contact and percolating filters is carefully, 
and on the whole fairly, drawn, although it is not 
quite clear whether the working costs quoted are 
strictly comparable. 
Assumption of the colloidal form is so charac- 
teristic a property of fecal matter that the 
author’s belief that the colloidal matter of sewage 
is derived in great measure from soap would seem 
to require some definite experimental support or 
reconsideration. 
The book is well indexed, and is provided with 
a useful bibliography. Percy Gaunt. 

THE PRODUCTION OF NEW VARIETIES 
OF PLANTS. 
Fundamentals of Plant-Breeding. By Dr. J. M. 
Coulter. Pp. xiv+347. (New York: D. 
Appleton and Co., 1914.) Price 6s. net. 
ROF. COULTER is entering the ranks of 
the writers of books on scientific subjects, 
as he already has a place amongst those who 
produce scientific books. In the volume before 
us he has certainly achieved a_ considerable 
measure of success in makin dificult matters 
fairly easy of comprehension by any erdinarily in- 
telligent person. The carping critic may perhaps 
object that the dose of science is sometimes con- 
tained in too abundant a vehicle of padding, but 
at least he will scarcely allege that the padding 
itself is totally devoid of flavour. 
The author has skimmed over many difficult 
and debatable matters with a freshness and 
vigour of expression which makes his book a 
pleasant one to read, and he has contrived to 
weave into the text a very considerable amount 
of theory and fact. Even those who are tolerably 
familiar with the work of plant breeding will 
prebably find much that is of interest in what we 
might perhaps describe as the more remotely 
relevant matter. The book is, of course, written 
from the American viewpoint, but it is good that 
people in this country should have brought forcibly 
to their notice the supremely important problems 
that underlie so much of scientific agriculture, in 
which an immense amount of capital is invested. 
The Americans take these problems seriously, and 
NO. 2383, VOL. 95] 

| the people are interested in the results which 
mean so much to the country, for it is from the 
soil and its living products that the permanent 
sources of wealth of a community must, after all, 
largely depend. 
Prof. Coulter deals with the various methods 
of raising new and valuable plants, of conserving 
what has been obtained by the application of 
rational, and therefore truly scientific, principles 
which enable disease to be successfully fought, 
and by which further improvements are to be 
secured. He also deals with the more outlying 
topics of forestry, the soil, search for new plants, 
the work of experimental stations, and so on, 
and he may be congratulated on the production 
of an instructive, and readable 
volume. 
We note a few poiats in connectien with which 
a future edition will, perhaps, afford an occasion 
for modification. The lettering of the figures on 
p. 11 is omitted; and surely Figs. 15 and 16 
should not be quoted from the text-book of which 
Prof. Coulter is joint-author, but from the original 
source, i.e. from Bonnier’s admirable paper on 
the effects of habitat on plant structure. Excep- 
tion might well be taken to the illustration on 
p- 5 of fluctuating and constant variation, on the 
ground that the potato tubers quoted are the 
result of vegetative, and not of sexual, repro- 
duction, and the illustration itself also strikes one 
as having an air of unreality about it. A serious 
misapprehension of Weismann’s position would 
probably be gathered by the uninstructed reader 
of p. 68, on which it is briefly stated that “ Weis- 
mann thought that all the characters of both parents 
are represented by ids in the fertilised egg. This 
was the necessary antecedent to ‘ amphimixis.’ 
Mendel, on the other hand, showed that characters 
are segregated in the reproductive cells.” 
Weismann would certainly have repudiated the 
justice of the contrast in this form. But, despite 
slips such as these, the book is a good one. 
interesting, 

OUR BOOKSHELF. 
The Earth: Its Life and Death. By Prof. 
A. Berget. Translated by E. W. Barlow. Pp. 
xXi+ 371. (New York and London: G. P. 
Putnam’s Sons, 1915.) Price 7s. 6d. net. 
Pror. Bercer has written in popular terms a 
physical history of the earth. He has endeavoured 
to discern the mode of its origin and to estimate 
its age, to describe the phenomena of the present 
living globe, and finally to forecast the manner 
of its death. He has certainly succeeded in 
rendering many difficult lines of reasoning clear 
and intelligible to the general reader. The book 
is in no part dull, and would not read like a 
| translation were it not that English equivalents 


