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POPULAR SCIENCE REVIEW. 
medical profession, and of most cliemists ; and if they will only condescend 
to study, the great mass of superficial readers will benefit by it. But it is 
not an easy hook, for it deals with great problems ; and as it is written 
conscientiously, it will rather astonish some people who follow blindly 
whatever the dominant school preaches. Letourneau is a philosophical 
evolutionist : he believes in spontaneous generation, and discredits all that one 
reads about germs. As a sensible man, he asserts the positivity of atoms, 
and thus defines life: “Life is a twofold movement of simultaneous and 
continual composition and decomposition, in the midst of plasmatic sub- 
stances, or of figurate anatomical elements, which, under the influence of 
this indwelling movement, perform their functions in conformity to their 
structure.” If we did not know it before, this sentence would lead us to 
believe that life is sufficiently mysterious and incapable of formulation. 
The references to the positive part of Biology are good and up to the day ; 
and the chapters which deal with function and reproduction and per- 
sistence are full of good original suggestions and careful quotations. 
Thus, in treating of the office of respiration, there is the following very 
suggestive sentence : “ Behind every biological activity there is an oxydation 
of the anatomical elements ; no organ escapes this law, and the nervous centres 
are as much in subjection to it as the other organic apparatus. Every 
thought, every volition, every sensation, corresponds to an oxydation of the 
living substance, as well as every secretion, every movement,” &c. There is a 
singular blunder on page 269, in which a Malpighian body of the kidney does 
duty for one in the bladder. Further on, the Brownian movement is stated 
to be caused by phenomena of attraction at short distances and belongs to 
the domain of capillarity ! — it has nothing to do, according to the author, 
with simple liquid currents. Due to the same cause that produces the 
motion of the vacuoles in the cavities of crystals, minute heat currents are 
certainly dynamical in this movement, which is so different from that of 
independent living things. Bathybius crops up, but its hypothetical nature 
seems hardly to have been understood; and an error of a distinguished 
British physicist is reproduced in the assertion that Dr. Mayer founded the 
“ great doctrine of the unity of forces.” Supposing that by this is meant 
the doctrine of the mechanical equivalent of heat and the theory of the 
conservation of energy, there is not the least justification for placing Mayer 
before Dr. Joule, of Manchester. Joule made the experiment, and proved by 
theory and practice what Mayer dreamed about and fancied, and never 
proved by experiment. 
Everyone who has translated a French scientific work will sympathize 
with Mr. Maccall ; and we do not wish in any way to detract from the credit 
due to him, when we suggest that before the book passes to a second edition 
some scientific man of standing should point out certain old-fashioned expres- 
sions, which would be all the better if Anglicized and modernized. 
AMERICAN STATE PUBLICATIONS. 
O NCE again we have to notice the wonderful series of scientific publications 
brought out under the auspices of the Government of the United States 
And we may worthily begin with the records of the labours of the Geologi- 
