the parsonage, others go down the village, and others part only in the
next parish. A man in his development runs for a little while parallel
with, though never passing through, the form of the meanest worm, then
travels for a space beside the fish, then journeys along with the bird
and the reptile for his fellow travellers; and only at last, after a
brief companionship with the highest of the four-footed and four-handed
world, rises into the dignity of pure manhood. No competent thinker of
the present day dreams of explaining these indubitable facts by the
notion of the existence of unknown and undiscoverable adaptations to
purpose. And we would remind those who, ignorant of the facts, must be
moved by authority, that no one has asserted the incompetence of the
doctrine of final causes, in its application to physiology and anatomy,
more strongly than our own eminent anatomist, Professor Owen, who,
speaking of such cases, says ('On the Nature of Limbs', pp. 39, 40): "I
think it will be obvious that the principle of final adaptations fails
to satisfy all the conditions of the problem."

But, if the doctrine of final causes will not help us to comprehend the
anomalies of living structure, the principle of adaptation must surely
lead us to understand why certain living beings are found in certain
regions of the world and not in others. The palm, as we know, will not
grow in our climate, nor the oak in Greenland. The white bear cannot
live where the tiger thrives, nor 'vice versa', and the more the
natural habits of animal and vegetable species are examined, the more
do they seem, on the whole, limited to particular provinces. But when
we look into the facts established by the study of the geographical
distribution of animals and plants it seems utterly hopeless to attempt
to understand the strange and apparently capricious relations which
they exhibit. One would be inclined to suppose 'a priori' that every
country must be naturally peopled by those animals that are fittest to