822 THE AMERICAN NATURALIST. [VoL. XXXIV. 
place of stimulation is indifferent, the writer states) was determined 
for ten animals, and found to vary from .2o second to .65. 
A comparative study of the results of these experiments ‘fails to 
discover anything . . . so far comparable to individual tempera- 
ments " as “sensitive and weak" or “ dull and strong." “Absence 
of correlations and inconstancy are the two significant features of 
the results." 
The value of this work, it would seem, lies chiefly in its suggestive- 
ness. Almost every page of the report points out some line of work 
which might claim months of careful study. Much of the evidence 
furnished by the experiments seems to us inconclusive because of an 
insufficient number of observations. Dr. Dearborn has, by the use 
of the “extensive” method, exposed himself to the criticism “ frag- 
mentary and superficial." R. M. Y. 
The Problem of Innate Ideas. — The third of Dr. Ad. Wagner's 
Studien und Skizzen aus Naturwissenschaft und Philosophie’ is a 
philosophic discussion of “innate ideas.” Of the two earlier papers 
of this series the first dealt with scientific thought and popular 
science, the second with the problem of free will. 
Dr. Wagner calls attention to the far too common avoidance of 
fundamental problems by natural scientists . . . “ der Naturgelehrte 
meistens sagen: Ach was! Ich bin Naturforscher. Lasst mich mit 
Eueren philosophischen Problemen in Ruhe! Die gehen mich 
nichts an." 
In this short essay the nature of knowledge is very clearly and 
concisely treated. In many respects Wagner's standpoint is Kan- 
tian. He considers space, time, and causation “forms” of thought. 
The latter part of the paper is devoted to the relations of the brain 
as the organ of mind to the “a priori” (commonly so-called) of 
knowledge. R. M. Y. 
Empirical Teleology.*— It seems unfortunate that Cossmann 
should have chosen a title so unattractive to the majority of biologists 
as “Elements of Empirical Teleology,” for there is much in his book 
worthy of their attention. 
1 Ueber das Problem der angeborenen (apriorischen) Vorstellungen. Berlin, 
Gebriider (eesti ne 1900. 77 pp. 
2 Co n, Paul Nikolaus. Elemente der empirischen Teleologie. Stuttgart, 
A. disi. ipe 
