550 Recent Literature. fJuly, 
—— We have received the following from a distinguished cor- 
respondent: . 
ALBANY, May 14, 1881. 
Gentlemen:—I have received the notice extracted from AM. 
NATURALIST, in reference to an invitation to the British Associa- 
tion for the Advancement of Science to meet in America in 1883. 
I approve of the invitation, which it will be necessary to repeat 
before its acceptance. 
It is well to begin the invitation in order that we may approach 
the object which sooner or later I believe will be accomplished. 
Very truly yours, James HALL. 
20: 
RECENT LITERATURE. 
Semper’s AmMIMAL LiFe as AFFECTED BY THE NATURAL CONDI- 
TIONS OF ExisTENCE.1—The author’s aim in preparing the lectures 
which he originally delivered before the Lowell Institute, at Boston, 
and which are here presented to the reading public, is expressed in 
the following words, to be found in the preface: “ It appears to me 
that of all the properties of the animal organism, variability 1s that 
which may first and most easily be traced by exact investigation 
to its efficient causes; and, as it is beyond a doubt the subject 
around which at the present moment the strife of opinions 1S most 
violent, it is that which will be most likely to repay the trouble of 
closer research.” Professor Semper, therefore, endeavors, and We 
are either of universal significance or, from his own point of "ied 
appear to offer favorable subjects for experimental treatment. The 
an original contribution to the general subject of evolution fro 
the point of view of experiments on the relations between animals 
and their environment, which may be largely made in the labora 
tory, as well as in the field. The subject of endeavoring to account 
or the origin of the variations of species, of seeking for the cod 
cient causes of variability, is not unfamiliar to American natura™ 
ists. Darwin professedly starts from the tendency to variation, 
and his theory, as such, ignores or opposes any thing like Lae 
marckianism or the influence of the environment on the organism. 
A few American writers have felt that we must endeavor to See 
the causes inducing the tendency to variation, and have sist 
been led to what we may call a modified, scientific form of La- 
as 
marckianism. Inorder that the organism may undergo change = 
ditions of Existence. By KARL Semper, Professor of the University of 
With two maps and 106 wood cuts. I2mo, pp. 472. 
. . * * Loi 2 
1 The International Scientific Series. Animal Life as Affected by es eee vo 
