functions, intellectual, moral, and others, are the expression or the
result, in the long run, of structures, and of the molecular forces
which they exert." It is quite true that I do so.

"Well, but," I am told at once, somewhat triumphantly, "you say in the
same breath that there is a great moral and intellectual chasm between
man and the lower animals. How is this possible when you declare that
moral and intellectual characteristics depend on structure, and yet
tell us that there is no such gulf between the structure of man and that
of the lower animals?"

I think that objection is based upon a misconception of the real
relations which exist between structure and function, between mechanism
and work. Function is the expression of molecular forces and
arrangements no doubt; but, does it follow from this, that variation in
function so depends upon variation in structure that the former is
always exactly proportioned to the latter? If there is no such
relation, if the variation in function which follows on a variation in
structure, may be enormously greater than the variation of the
structure, then, you see, the objection falls to the ground.

Take a couple of watches--made by the same maker, and as completely
alike as possible; set them upon the table, and the function of
each--which is its rate of going--will be performed in the same manner,
and you shall be able to distinguish no difference between them; but let
me take a pair of pincers, and if my hand is steady enough to do it,
let me just lightly crush together the bearings of the balance-wheel,
or force to a slightly different angle the teeth of the escapement of
one of them, and of course you know the immediate result will be that
the watch, so treated, from that moment will cease to go. But what