1066 The Relations of Mind and Matter. _[November, 
tive organism, is strikingly complete. We may, as an analogy, 
view this organism as having a delicately sensitive surface, which 
remains unaffected while it is kept from the influence of the nerve 
current, like the photographic plate when kept from the light. 
But the instant the energy of this current touches it a pictured 
image is produced which closely represents the object which 
instigated the nerve current. -And this picture becomes a per- 
manent condition of the mind. It indicates a fixed change in its 
motor organization. In this respect, however, the mind repre- 
sents a photographic plate of extraordinary sensitiveness, one in 
which we might imagine that each picture sinks below the sur- 
face, or a new sensitive surface is immediately formed over it. 
We may pursue this analogy of the organism of the mind to 
conceivable photographic conditions somewhat further, and reach 
other interesting conclusions. In .this connection the relations 
which our mental impressions bear to each other form an impor- 
tant subject of. inquiry. These relations are of two kinds, one of 
similarity, either direct or analogous, and the other of contiguity 
in time of reception. Each new impression seems to’ connect 
itself with all preceding similar impressions in such a manner that 
consciousness of the one tends to recall the other to conscious- 
ness, this effect being the more marked the greater the 
As intimate a relation exists between i i ived together, 
although they may be very unlike. Their’ connection in time serves 
as a link of combination. They elbow each other in the mind, as 
it were, . 
_ These are the two distinguishing features of remembrance, and 
seem to point to two distinct conditions under which the mind re- 
tains its images. In regard to contiguity in time the recall of 4 
mental image seems to recall the whole surface condition of the 
(I have witnessed it even after a year), on breathing again upon it the shadowy 
- form emerges. Or if a sheet of paper, on which a key ôr other object is laid, be 
carried for a few moments into the sunshine and then instantaneously viewed in the 
dark, the key being simultaneously removed, a fading ‘spectre of the key on the 
paper will be seen; and if the paper be put away where nothing can disturb it, and 
so kept for many months, at the end thereof, if it be carried into a dark place 
a paea hot metal, the spécire of the key will come forth, In the cas¢ 
t than paper, the spectres ot many different ob- 
; pria may pTi isai in succession laid originally thereupon, will, upon 
arming, emerge in their proper order. Indeed, I believe that a shadow never falls 
a wall without leaving thereupon its permanent trace—a trace _ pat san 
jle by resort to proper measyres ” (Physiology, p. 288), 
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