THE 
AMERICAN NATURALIST. 
VoL. xu. — SEPTEMBER, 1878. — No. 9. 
THE SENSORY ORGANS—SUGGESTIONS WITH A 
VIEW TO GENERALIZATION! 
BY FRANCIS DERCUM, M.D., PH.D. 
ERHAPS in the whole range of physiological and anatomical 
studies, no subject is invested with a deeper interest than that 
of the sensory organs. It is by means of them that we first 
become aware of our own existence; it is by means of them, in 
other words, that consciousness is first awakened in us, and it is 
through them that we subsequently continue our acquaintance 
with the outer world. It would be of great importance, were it 
possible, to arrive at some general conclusion regarding their 
morphology—some general view regarding the essential elements 
or the essential conditions of their structure. Judging from our 
knowledge at present it may seem that an attempt in this direc- - 
_ tion would be fruitless. Notwithstanding there are several prime 
facts which do not seem to have attracted the general attention © 
which their. importance deserves, and these when placed in their 
proper relations may give a new character to the subject, and 
perhaps open new avenues for investigation. 
It will be interesting, therefore, to hastily review what is known 
_ regarding the constant elements of the various sensory organs. 
Under this head, of course, it will be unnecessary to consider the 
= more or less mechanical arrangements by which force is con- 
ducted, and we will adhere, therefore, to that part of the litera- 
_ ture only which treats of the ultimate structures by which impres- 
sions appear to be received. 
1 Read before the Alumni Society of the Auxiliary Department of the University 
2 o a T March 29, 1878. 
VOL. XIL.—NO. 
