1896.] The Biologie Origin of Mental Variety : 973 
the other wire we will imagine to be connected with a visible 
index, the rise and fall of which is determined by the rise and 
fall of a barometer and other electric apparatus, also situate 
on the roof. Under this illustration the ringing of the sonor- 
ous bell and the moving of the visible index are the analogues 
of our sensations, the electric wires correspond with our 
nerves, the wind-gauge and barometer with our end-organs, 
and the wind and temperature with their external stimuli. 
And since, under these conditions, by merely changing the 
wires here at the desk and connecting the barometer with the 
bell, and the wind-gauge with the index, the “sensory ” results 
would be completely reversed from what they formerly were, 
so, therefore, we have here a perfect example of what Prof. 
James means, by saying that all depends on the place in the 
cortex with which the currents or wires are connected. And, 
going now a step further, these conditions also illustrate what 
Prof. James has wholly neglected to consider, namely, the evolu- 
tionary influences which made the “places” in our cortex 
different, and those which first connected them with the par- 
ticular end-organs and stimuli with which they are now per- 
manently connected ; and these, we quickly perceive, are the 
important points in our great main problem. Precisely what 
we want to know is how we came to have the variety of senses 
that we do have, and how they came to be joined to the par- - 
ticular stimuli to which they are joined. From time out of 
mind mankind has naively taken for granted that the now 
existing relationship between sensations and their stimuli is 
an eternally permanent one of immediate cause and effect. 
But, as we have pointed out, this cannot be the case if the 
currents in all the sensory nerves are alike, and if, as Prof. 
James contends, it is alone the “ place” in the cortex which 
determines the sort of sensation that shall respond to any sort 
of current or stimulus which may run to it. In this case it 
should be plain that it isin the characteristic differences of 
these“ places ” and in the evolutionary origin of the same, and 
of their permanent connection with their present peripheral 
organs, that the secrets must lie which we are in search of. 
Surely no one, under the conditions of our illustration, would 
