1897,] The Biologic Origin of Mental Variety : 9 
Turning now to the postulate of many primary senses, we 
have no longer to account for the birth of new senses. Our 
problem, here, is to determine how our present senses were shut 
in, and all others shut out; and this is the problem of the 
origin of our sense organs, and of the establishment and per- 
petuation of the articulate processes, mediate or intermediate 
which they perform. 
(M4 w). The Weismannian principle, here, of course can have 
no immediate bearing on the birth of different senses, since all 
of ours, and many more are supposed to have existed origin- 
ally. Under this postulate taken with the doctrine of “ through 
currents directly articulate,” our problem would be at its sim- 
plest ; for the same couplings of senses and stimuli that exist now 
are likely to have continued, fixedly, from the beginning. The 
perpetuation of any particular sense, under these conditions, 
must have been decided jointly, on the one hand, by the need 
which the developing organism had of being adjusted to cer- 
tain environmental forces rather than others; and on the other, 
by the capability of the organism to fit itself to, and to main- 
tain the peculiar neural modes (energies) correspondingly to 
these forces. As examples of this sort of development we should 
explain the skin to be a peripheral organ which has preserved 
our sensibility to heat and to cold through the profitability of 
preserving the developing creature from temperature extremes, 
at the expense of losing sensibility to an unknown number 
of other forces. Or perhaps, and as I suspect this is a far more 
profound statement, it may quite well have been that it was 
the adaptability of certain molecular sense-forms for general 
physiological organization, that originated such organization 
in lines of their correspondent stimuli, rather than in other 
lines; as for instance in the line of a creature suspectable to 
our environmental stimuli, rather than in the line of a creature 
susceptable, let us say, to electrical influences. 
(M41). Under the Lamarckian principle the reasons for the 
selection and perpetuation of the particular sense elements, 
which now make up our mental equipment, would be so similar 
to those set forth in our last above paragraph, that they need 
not be here repeated. It is the method of general biologic 
growth that would be different in these two cases. 
