1898] SOME NEW BOOKS 421 
to the historian of the future. The successes have been in an in- 
creased knowledge of the facts and governing principles of the world 
around us, and in the application of them to our benefit. The failures 
have lain chiefly in the field of social economy, in which the advance 
has been incommensurate with that in the region of physics. 
The striking feature of the century has “been the discovery and 
application of scientific and mechanical principles entirely unknown 
to previous ages ; discoveries comparable to the invention of fire, of 
writing, of geometry, or of printing; applications that have revolu- 
tionised the mode of life of nearly all the world, bringing changes both 
wide and deep where change had been unknown for centuries, or even 
for millennia. Chief among these are the means of communication by 
railways, steamships, the electric telegraph, and the telephone. Then 
come modes of lighting, friction matches, gas light, and electric light. 
The knowledge of light itself, and its action on matter, with “the 
marvellous applications to photography, the Rontgen rays and spec- 
trum analysis, by which last our knowledge of the distant universe 
has been so enormously extended in so many directions. Minor 
mechanical inventions of a novel order are the phonograph, the type- 
writer, and the cycle. Among scientific theories, whose practical 
application, though not always so direct or obvious, has profoundly 
altered our ways “of thought, or given us fresh mastery over matter, 
Mr Wallace notes the following :—The doctrine of the conservation 
ot energy; the molecular theory of gases; the atomic theory as the 
foundation of modern chemistry ; the uses of dust; a knowledge of 
meteors and the meteoritic theory of the universe (the latter perhaps 
not so generally accepted as to have a right to rank in the present 
category); the hypothesis of a glacial epoch (in which also Mr 
Wallace goes further than many admit); the vaster conception of 
the antiquity of man; the cell theory and the theory of recapitula- 
tion in embryology (where, likewise, a hint of recent criticism would 
not have been misplaced); the germ-theory of disease and the func- 
tion of leucocytes, from which conceptions Mr Wallace, not quite 
fairly, separates antiseptic surgery ; the use of anaesthetics : and the 
acceptance of the theory of organic evolution, an acceptance due 
chiefly to the labours of Darwin, whose “work will always be con- 
sidered as one of the greatest, if not the very greatest, of the eens 
achievements of the nineteenth century.” 
This first half, or rather, less than half, of the book is a walt 
balanced and thoroughly interesting review, making its chief appeal 
to the ordinary intelligent reader. It might have been written, per- 
haps not quite so well, by any competent man of science. The second 
section of the book, dealing with the failures of the century, could 
have been written only by Mr Wallace. As an expression of the con- 
victions of an eminent naturalist and thinker on many of the most 
important problems of our day, it has a value by virtue of that personal 
element, and demands the attention of all, whether they agree with 
‘ its opinions or no. The list opens curiously with a strong statement 
of the case for phrenology, the neglect of which is regarded as one 
of the chief failures; the chapter undoubtedly provokes one to a re- 
consideration of the subject. Of similar nature is the opposition to 
hypnotism and physical research, so prevalent among scientific men. 
