Inheritance of Acquired Characters 247 
Remaining surface of digits, middle of forehead, olecranon. 
Glabella, chin, clavicle. 
Palm, buttock, popliteal space. 
Neck. 
Back. 
Lower eyelid, cheek. 
Nipple, loin. 
COPS OR eG 
These two tables show the great differences in the range 
of sensitiveness to cold and to warmth in different parts of 
the body. I doubt if any one will attempt to show that 
these differences of range of sensation can be accounted for 
either by natural selection or by the Lamarckian hypothesis. 
Of course, it does not necessarily follow that, because this 
is true for the warm and cold spots, that it must also be true 
for the tactile organs; but I think that the fact of such a great 
difference in the responsiveness to cold and to warmth in 
different parts of the body should put us on our guard against 
a too ready acceptation of Spencer’s argument. More espe- 
cially is this seen to be necessary, when, as has been shown 
above, the distribution of the touch-organs themselves by no 
means closely corresponds to what we should expect, if they 
have developed in response to contact, as Spencer maintains. 
_ The other main argument advanced by Spencer to fortify 
the theory of the inheritance of acquired characters, and at 
the same time to show the inadequacy of the theory of natu- 
ral selection, is based on the idea of what he calls the “co- 
operation of the parts” that is required in order to carry out 
any special act. Spencer contends that “the relative powers 
of codperative parts cannot be adjusted solely by the sur- 
vival of the fittest, and especially where the parts are nu- 
merous and the codperation complex.” 
Spencer illustrates his point by the case of the extinct 
Irish elk, whose immensely developed horns weighed over 
a hundredweight. The horns, together with the massive 
skull, could not have been supported by the outstretched 
