Sept. 16, 1886] 
beyond dispute is that our teachers have wretched text- 
books in geography, and Germany has been held up to 
us as the model to follow in this asin many other respects 
in regard to geographical teaching. The Germans (as 
Mr. Chisholm points out in his interesting preface) have 
had long experience in working out an advanced system 
of education ; they know that a limited period must be 
turned to account for the thorough teaching of a great 
variety of subjects, and accordingly they have learned to 
distinguish between what is indispensable as a ground- 
work and what must be omitted. In this country the 
study of geography is mainly a work of memory—the 
names of towns, rivers, mountains, with their populations, 
lengths, and heights. This and similar details are pre- 
cisely those on which the Germans lay least stress, and 
as Mr. Chisholm has “earnestly endeavoured to guide 
himself by German examples,” he anticipates that his 
book will appear more remarkable for what it omits than 
what it contains. Stated in his own words his object has 
been, in the first place, to draw a mental picture of the 
different countries and regions of the world, giving due 
relief to what is most distinctive in each region, and, 
secondly, to give special prominence to the relation of 
cause and effect, so as to enable pupils to realise that in 
geography there is something to understand as well as to 
commit to memory, in other words, to make geography a 
mental discipline as well as a body of instruction. Of 
course there is important work for the memory in geo- 
graphy as in every other branch of education, and this 
the author recognises, and provides for in his tables and 
printing. He insists, too, on the vital necessity of maps, 
without which there can be no adequate knowledge of 
geography. A text-book is supplementary to an atlas, 
and does not supersede it. These are high ideals which 
Mr. Chisholm sets before him ; let us see how he fulfils 
them. 
The whole volume contains 320 pages. ‘The first 60 
are devoted to an introduction dealing with mathematical 
and physical geography, which, as explained in the 
preface, is designed primarily for teachers, and is not 
intended to form part of the course for the pupils 
oa they have gone through the whole body of the 
ook. 
The introductionis followed bya description of continents 
and countries. Of the 260 pages which remain for this 
purpose, Europe fills 150 pages, Asia 45, Africa 16, and 
America 32. The proportions are based on the degree 
of knowledge which an educated English boy or man 
should have of the respective countries and continents. 
Some of the divisions are original. Thus English 
counties are divided into corn and grazing, the countries 
of Asia into monsoon and non-monsoon countries. We 
have specially examined the sections devoted to the 
countries of Eastern Asia, for the sins of ordinary British 
school geographies are more apparent here than else- 
where—the sins, namely, of stereotyped inaccuracy, and 
of strings of names and numbers. Mr. Chisholm has not 
a superfluous line in any of these sections, the informa- 
tion is of the latest kind, and all the knowledge that the 
average boy requires of the countries is put in a short 
space. 
As an instance of the care with which the work 
_is done it may be mentioned that the puzzling variations 
of some Japanese names (e.g. Fujinoyama, Fujisan) are 
given and explained. On the whole, we are convinced 
that there is at present no school geography in the English 
language more calculated to give adequate and intelligent 
instruction in that subject than this, and can therefore 
strongly recommend it to those teachers who have 
lamented the absence of a sound text-book. It is to be 
hoped that Mr. Chisholm may see his way to producing 
a smaller work about half the size and price of this book 
for lower classes. 
NATURE 
467 
SS SS ES eee 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions ex- 
pressed by his correspondents. Neither can he undertake to 
return, or to correspond with the writers of, rejected manu- 
scripts. No notice is taken of anonymous communications. 
[The Editor urgently requests correspondents to keep their letters 
as short as possible. The pressure on his space is so great 
that it is impossible otherwise to insure the appearance even 
of communications containing interesting and novel facts.) 
Physiological Selection and the Origin of Species 
As Mr. Romanes has referred to my article in the current 
number of the Fortnightly Review, and stated that he is prepared 
to answer what he terms ‘the very obvious exceptions” which I 
have taken to his theory, I shall be glad to be allowed to state, 
very briefly, what those exceptions are, and to give an illustra- 
tion of one of the more important of them. en 
(1) Mr. Romanes makes a great deal of the alleged “‘inutility 
of specific characters,” and founds upon it his extraordinary 
statement that, during his whole life, Darwin was mistaken in 
supposing his theory to be ‘‘a theory of the origin of species,” 
and that all Darwinians who have believed it to be so have 
blindly fallen into the same error. TI allege, on the contrary, 
that there is no proof worthy of the name that specific characters 
are frequently useless, and I adduce a considerable series of facts 
tending to prove their general utility. ‘ 
(2) In support of his view as to the swamping effects of inter- 
crossing, Mr. Romanes objects to the assumption of Darwin, 
“that the same variation occurs simultaneously in a number of 
individuals,” adding: ‘* Of course, if this assumption were 
granted, there would be an end of the present difficulty ™; and 
his whole argument on this branch of the question rests on the 
assumption being false. I adduce evidence—copious evidence— 
that the supposed assumption represents a fact, which is now one 
of the best-established facts of natural history. : 
(3) Mr. Romanes states, as the special feature of his physio- 
logical varieties, that ‘‘ they cannot escape the preserving agency 
of physiological selection.” He gives no particle of proof of 
this, while I show that, on the contrary, it is hardly possible for 
them to survive to a second or third generation. It is on this 
point that I wish to give an illustration. Mr. Romanes speaks 
of his supposed variations as ‘‘showing some degree of sterility 
with the parent form,” while continuing to be fertile «© within 
the limits of the varietal form”; but I hold that any such 
variety (beyond single individuals) can hardly exist, while he 
has adduced no proof whatever of their existence. To show the 
improbability of their existence, let us suppose a definite case. 
In a given species there is born an individual, A, which is in- 
fertile with the bulk of the species, but fertile with some few 
individuals of the opposite sex, a, 4, c, Let there be a second 
individual, E, born from other parents in another part of the 
area occupied by the species, and fertile only with e, /, g- Other 
individuals, K, P, R, &c., may have similar relations, each 
infertile with the bulk of the species, fertile only with a few 
individuals which may be termed their physiological comple- 
ments. Now each of these, separately, is a physiological 
variety, but the whole set, A, E, K, P, R, do not form one, but 
five distinct varieties. To form one variety all of them must 
be fertile with the same identical set of individuals of the 
opposite sex, and this seems to me to be so highly improbable 
that it must not be assumed till rigidly proved. Yet there is 
not one passage in Mr. Romanes’ paper to show that he 
recognised this difficulty; on the contrary, he always speaks 
as if any number of separate physiological variations within one 
species must necessarily form one variety. It will easily be 
seen that the chances against any single variety of this nature 
being preserved are overwhelmingly great. For, first, at least 
two of the complementary individuals must survive to the 
breeding-season, and the chances against this are measured by 
the fertility of the species. If it produces ten young each 
year, the chances are between nine and ten to one against any 
one of them surviving. The chances against the /wo complements 
surviving will be about ninety to one ; and then there remains the 
chances against the two meeting at the breeding-season, for, by 
the assumption, there is nothing whatever to bring them together 
but chance, and this may be any number of thousands to one. 
There are, no doubt, other possible cases in which the physio- 
logical variety might be continued, but, as I have shown in my 
