y The Amerwan Naturalist. [August, 
ance of certain forms of skeletal structures. And I am able to add 
that in the markings of animals—e.g., butterflies—characters every- 
where degenerate whose present or former use cannot be discerned, 
which we must regard as non-essential. 
‘ Weismann supposes that even in those cases in which adaptation 
is not demonstrated it is really present. But such an assumption 
belongs to the domain of faith. 
** We ought, on the contrary, to say: We know that definite stimuli 
must produce an effect on or in the organism ; that they must give rise 
to definite changes of form, definite character, whether these be use- 
ful to the organism or not. 
«When we maintain this we take our stand, not on mere assump- 
tions, but on physiological facts. Normal physiology and pathology 
in like measure speak for us with the weight of all their fundamental 
truths. 
** Thus there is certainly a physiological basis for the belief that the 
above-described variations of the sponge-skeleton are simply to be as- 
cribed to changes of external, z.e., of nutritive conditions, of the 
material composition of the body." 
The translator has performed an excellent service. We cannot but 
agree with him in some remarks in his preface as to the editorial con- 
duct of the English periodical Wature. He complains of the exclusion 
of articles which do not coincide with the views of the editor of the 
department of Natural History. On this we observe that such ex- 
clusions, no doubt, often occur, but though it may not be commended 
as judicial, it is within editorial right. But mutilation or alteration of 
articles, as is sometimes practiced by that periodical, is clearly not 
within editorial right, and to this practice exception may be still more 
fairly taken.— EZ. D. Cope. 
Geddes and Thompson on the Evolution of Sex.'—In 
this book we have a systematic résumé of what is known on the subject 
of sex, with inferences which appear to the authors reasonably to flow 
from the facts. The work is divided into four ** books," viz.: 
I. Male and Female; II. Analysis of Sex,—organs, tissues, cells ; 
III. Processes of Reproduction; IV. Theory of Reproduction. The 
. work done in this direction has been very large in the last few 
years, and the time was ripe for the presentation to the public of just 
such a work as the present. The subject is not only intrinsically 
interesting, but it has the closest relation to the general question of 
1 The Evolution of Sex. By Prof. Patrick Geddes and J, Arthur Thompson. 8v0, 
PP. 322. From the Contemporary Science Series. London: Walter Scott. 
Y 
