5i8 The American Naturalist. [June, 
MEASUREMENT OF MAN'S REASON. 
How many are twice two ? Twice ten ? Easy enough to 
tell. How many are twice 17.648? Seven times that? 
Twelve times that ? The mental operations required are those 
we have just been measuring, and we who have perceived in 
them the highest grade will succeed here the best. First at- 
tention to impression and sensation, then correctness, and 
finally, rapidity. All these tests to be recorded. Thus we 
may progress through mathematics, logic, philosophy, and so 
on to the end, practicing continually our first and fundament- 
al rules of Attention, and Correctness of Impression, or Sensa- 
The thoughtful man can follow this system out in detail, can 
perceive how it can be accomplished. I can see how, by the 
introduction of some such system, not only the average mental 
capacity or power of a nation or a people might be measured, 
the result announced in figures, and a comparison made with 
other nations; also that its use might tend to increase that ca- 
pacity and power. 
Such are the higher uses of Anthropometry. The hitman men- 
tal capacity to understand things is nearly allied to its capacity 
to see things. If one can be done I should not despair of the 
other. Whatever can be done with either must be by experi- 
ment directed by observation, Experiments must be repeated 
and the observations recorded. This means counting and 
measuring ; and this applied to man is the Science of Anthro- 
pometry. 
These are some of the possibilities of Anthropometry, but 
they are as yet far beyond the scientists of the United States. 
We must content ourselves for the present with obtaining 
full, complete, and reliable tables of measurements of the phy- 
sical peculiarities of the various races which inhabit our coun- 
try. This should be our immediate contribution to the world's 
MICROSCOPY.' 
The Retina of the Bird. — CajaP recommends the 
method of Golgi for the study of the retina. He proceeds as 
1 Edited by C. O. Whitman, Clark University, Worcester. 
