248 Evolution and Adaptation 
neck without many and great changes of the muscles and 
bones of the neck and of the fore-part of the body. Unless, 
for instance, the fore-legs had been also strengthened, there 
would be failure in fighting and in locomotion. Since “we 
cannot assume spontaneous increase of all these parts pro- 
portionate to the additional strains, we cannot suppose them 
to increase by variations one at once, without supposing the 
creature to be disadvantaged’ by the weight and nutrition of 
the parts that were for a time useless, — parts, moreover, 
which would revert to their original sizes before the other 
needful variations occurred.” 
The answer made to this argument was that codrdinating 
parts vary together. In reply to which Spencer points to 
the following cases, which show that this is not so: The 
blind crayfish in the Kentucky caves have lost their eyes, 
but not the stalks that carry them. Again, the normal 
relation between the length of tongue and of beak in some 
varieties of pigeons is lost. The greater decrease in the 
jaws in some species of pet dogs than of the number of 
their teeth has caused the teeth to become crowded! “I 
then argued that if codperative parts, small in number, 
and so closely associated as these are, do not vary together, 
it is unwarrantable to allege that cooperative parts, which are 
very numerous and remote from one another, vary together.” 
Spencer puts himself here into the position of seriously main- 
taining that, because some coéperative parts do. not vary to- 
gether, therefore no codperative parts have ever done so, and 
he has taken this position in the face of some well-known 
cases in which certain parts have been found to vary together. 
In this same connection Spencer brings up the familiar 
piece de résistance of the Lamarckian school, the giraffe. He 
recognizes that the chief traits in the structure of this animal 
are the result of natural selection, since its efforts to reach 
1It is curious that Spencer does not see that this case is as much against his 
point as in favor of it, since the unused teeth did not also degenerate. 
