1874.] Notices of Books. Er5 
the muscles. Have we not even heard of people thinking them- 
selves hungry? ‘The ‘ physical seat of ideas” is discussed in 
this same chapter, where we also find a physical treatment of 
memory, retention, or acquisition, which is defined as ‘the 
power of continuing in the mind impressions that are no longer 
stimulated by the original agent, and of recalling them at after- 
times by purely mental forces.” Professor Bain explains 
memory as an effect produced by the continuation in a weaker 
form of the original impression which evoked the original nerve- 
current. Just as when we hear the last clang of a bell an after- 
impression of a feeble kind remains on the ear. But surely we 
cannot imagine, in the case of memory, that the nerve-currents 
are always flowing; if so, why is the effort of memory ever 
necessary? If so, again, have we not motion produced from 
nothing, or at least an original impulse producing indefinitely 
continuous impulses, after the manner of perpetual motion ? 
The book is full of sound logic; it is the work of an accurate 
and active mind. It is a physico-metaphysical treatise, and to 
the man of science sadly lacks the absoluteness of the experi- 
mental fact. It is most pleasurable to read this book, yet we 
confess that when we arrive at the last page we find ourselves 
just as wise (or rather, ignorant) as we were before, in regard to 
the nature of mind. 
On the Origin and Metamorphoses of Insects. By Sir Joun 
Lupsock, M.P., F.R.S. Illustrated. Macmillan and Co. 
London; 1874. 108 pp., crown 8vo. 
SIR JOHN LuBBOCK is well known to the world as an archeologist 
and anthropologist, and perhaps less well as an entomologist. 
Yet he has contributed no less than thirty-five papers to the 
Royal Society, and to various magazines, on entomology during 
the last twenty years; and, as he is not yet forty, we perceive 
that he must have studied the subject at a very early age. His 
first paper, ‘‘On Labidocera,” appeared in the ‘‘ Annals and 
Magazine of Natural History” for 1853. 
The little work before us embodies in a popular form many of 
the more interesting results of his observations condensed from 
the above-mentioned memoirs. The articles have already 
appeared in ‘“ Nature,” and the work forms the second volume 
of the Nature Series of books, which Messrs. Macmillan are now 
publishing. 
The main subjects discussed are the classification, origin, and 
the nature of the different metamorphoses of insects; various 
views are traced, from the old standard “‘ Entomology ” of Kirby 
and Spence, one of the Bridgewater treatises, to the more recent 
memoirs of Miiller, Agassiz, and Packard. ‘The intelligence of 
insects comes out in a remarkable light. Many of our readers 
will remember Sir John’s tame wasp at a recent meeting of the 
British Association, He remarks ‘we are accustomed to class 
