is inexplicable on the hypothesis of diffusion. The author as- 
cribes to the lung tissue a distinct secretory power for both 
O and CO,, a quality which is possessed by the swim-bladder 
of fishes. 
Dr. H. p. Bowditch's " Hints for Teachers of Physiol- 
ogy'" is an admirable little book, intended for the use of 
teachers in grammar schools and upward. It contains nu- 
merous suggestions of methods by which text-book instruc- 
tion may be supplemented by "simple observations and ex- 
periments on living bodies or on organic material, thus im- 
parting to pupils a knowledge of the foundation on which 
physiology rests, and, at the same time, bringing the impress- 
ions made on the senses to aid the memory in retaining the 
facts communicated in a purely didactic way." Digestion, 
circulation, motion, voice, animal heat, respiration, vision, 
and hearing are treated, but by no means exhaustively, for the 
author does not attempt a complete treatise on physiology. 
The hints are so excellent that it is a pity that the work is 
not more full. 
PSYCHOLOGY. 
MiNOT's Report on Diagram Tests.— During the past 
year a large number of postal cards were distributed, each 
bearing the printed request : " Please draw ten diagrams on 
this card, ivithoiit receiving any suggestion from any other 
person, and add your name and address'' 
The committee has received for examination 501 postal 
cards, with diagrams upon them. A few of the cards had more 
than ten diagrams upon them, and of such cards only the first 
ten diagrams on each were counted. A few cards had less 
than ten diagrams. 
The cards were divided into three sets; i, men ; 2, wom- 
en ; 3, without names. Each set of cards was numbered, and 
the diagrams on each card numbered. 
Such tests as the diagrams, on which this report is based, 
demonstrate the slightness of our real individual distinction 
and separation. The similarity is so great that the same vis- 
ual images arise in many of us with approximately the same 
We come here to a domain of psychology which has been 
but little and inadequately studied, namely, the frequency 
' "Guides for Science Teaching," No. 14, pp. 5S, Boston, D. C. Heath & Co., 
