70 NATURE 
[JUNE 13, 1912 
In these fundamental works Wallace appears 
as a disciple of Lyell in uniformitarianism, and 
a follower of Dana as regards the stability and 
permanence of continental and oceanic areas, for 
which he advances much original evidence. He 
taxes his ingenuity to discover every possible 
means of dispersal of animals and plants other 
than those which would be afforded by hypo- 
thetical land connections; he considers every pos- 
sible cause of extinction other than those which 
are sudden or cataclysmal. ‘‘ Island Life ’’ is in 
itself a great contribution, the starting point of 
all modern discussion of insular faunas and floras. 
The conservative theory of dispersal is applied 
in an original way to explain the arctic element 
in the mountain regions of the tropics, as opposed 
to the low-temperature theory of tropical lowlands 
during the Glacial Period; his explanation is 
founded on known facts as to the dispersal and 
distribution of plants, and does not require the 
extreme changes in the climate of tropical low- 
lands during the Glacial Period on which Darwin 
founded his interpretation. The causes and in- 
fluence of the Glacial Epoch are discussed in an 
exposition of Croll’s theory. In this connection 
may be mentioned one of Wallace’s original geo- 
logical contributions, in the “Glacial 
Erosions of Lake Basins,’’ published in 1893, 
namely, his theory of glacial erosion as a means 
of explaining the origin of valley lakes of glaci- 
ated countries. 
The natural trend of Wallace’s thought as to 
the ascent of man is first shown in the three 
anthropological essays of. 1864, 1869, and 1870, 
contained in the volume ‘‘ Contributions to the 
Theory of Natural Selection.’”’ This work, pub- 
lished in 1871, includes all his original essays 
from 1855 to 1869 on selection, on colour, and 
human evolution, which foreshadow the later 
development of his speculative philosophy. In his 
article of 1864, ‘‘ The Development of Human 
Races under the Law of Natural Selection,’’ he 
first pointed out that so soon as man learned to 
use fire and make tools, to grow food, to domesti- 
cate animals, to use clothing, and build houses, 
the action of natural selection was diverted from 
his body to his mind, and thenceforth his physical 
form remained stable, while his mental faculties 
article 
improved. His subsequent papers, ‘‘ The 
Elements of Natural Selection as Applied to 
Man’”’ of 1869, ‘‘On Instinct in Man and 
Animals ’’ of 1871, mark the gradual divergence 
of his views from those of Darwin, for in his 
opinion natural selection is believed to be inade- 
NO. 2224, VOL. 89] 
quate to account for several of the physical char- 
acteristics of man, as well as his speech, his colour 
sense, his mathematical, musical, and moral at- 
tributes. Here is found the opinion that a 
superior intelligence is guiding the development 
of man in a definite direction and for a definite 
| purpose, which finds final expression in the largely 
metaphysical volume of rg11._ It is also prophetic 
of later thought that we find at the end of the 
closing pages of ‘‘ The Malay Archipelago ”’ the 
first statement of the feeling which so many 
travellers have experienced from a comparison of 
the natural and so-called civilised condition of 
man that ‘‘ social evolution from barbarism to 
civilisation ’’ has not advanced general human 
welfare. These humanitarian and partly social- 
istic ideas are developed in a series of recurrent 
essays between 1882 and 1903, including ‘* The 
Nationalisation of Land,’’ and ‘‘ Studies Scientific 
and Social.’’ 
Our perspective has covered a long, honourable 
span of sixty-five years into the beginnings of 
the thinking life of a natural philosopher whose 
last volume, ‘‘ The World of Life,’’ of the year 
Ig1I, gives as clear a portrayal of his final 
opinions as that which his first essay of 1858 
affords of his early opinions. We follow the cycle 
of reflection beginning with adaptation as the 
great problem, adaptation as fully explained by 
selection, and closing with adaptation in some of 
its phases as entirely beyond human powers of 
interpretation, not only in the evolution of the 
mind and spiritual nature of man, but in such 
marvellous manifestations as the scales of butter- 
flies or the wings of birds. From our own intel- 
lectual experience we may sympathise with the 
rebound of maturity from the buoyant confidence 
of the young man of thirty-five who finds in selec- 
tion the entire solution of a problem which has 
vexed the mind and aroused the scientific curiosity 
of man since the time of Empedocles. We have 
ourselves experienced a loss of confidence with 
advancing years, an increasing humility in the 
face of transformations which become more and 
more mysterious the more we study them, 
although we may not join with this master in 
his appeal to an organising and directing prin- 
ciple. Younger men than Wallace, both among 
the zoologists and philosophers, of our own time 
have given a somewhat similar metaphysical solu- 
tion of the eternal problem of adaptation, which 
still baffles and transcends our powers of experi- 
ment and of reasoning. 
Henry FartrFiELD OSBORN. 
