The shape, also, of the pelvis might affect by pressure the
shape of certain parts of the young in the womb. The laborious breathing
necessary in high regions tends, as we have good reason to believe, to
increase the size of the chest; and again correlation would come into play.
The effects of lessened exercise, together with abundant food, on the whole
organisation is probably still more important, and this, as H. von
Nathusius has lately shown in his excellent Treatise, is apparently one
chief cause of the great modification which the breeds of swine have
undergone. But we are far too ignorant to speculate on the relative
importance of the several known and unknown causes of variation; and I have
made these remarks only to show that, if we are unable to account for the
characteristic differences of our several domestic breeds, which
nevertheless are generally admitted to have arisen through ordinary
generation from one or a few parent-stocks, we ought not to lay too much
stress on our ignorance of the precise cause of the slight analogous
differences between true species.
UTILITARIAN DOCTRINE, HOW FAR TRUE: BEAUTY, HOW ACQUIRED.
The foregoing remarks lead me to say a few words on the protest lately made
by some naturalists against the utilitarian doctrine that every detail of
structure has been produced for the good of its possessor. They believe
that many structures have been created for the sake of beauty, to delight
man or the Creator (but this latter point is beyond the scope of scientific
discussion), or for the sake of mere variety, a view already discussed.
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