1887 ] | Recent Literature. 465 
Hence heat is thus changed at a proper distance from the sun. 
The only adverse criticism we have to offer to this theory follows 
Professor Kedzie’s assumption that the physical basis of universal 
` energy (the ether) is of infinite extent. If this be assumed, his 
other assumption, that it is fu// of energy, falls to the ground: 
it could never get full, and energy radiated into it would be truly 
lost and would never return. If, now, the ether be supposed to 
have a limiting boundary, Professor Kedzie’s theory has a much 
more certain basis, and, indeed, so far as regards the necessary 
return of energy, may be fully accepted. 
Professor Kedzie advances the theory that sun-spots are dy- 
namic shadows or regions of lower temperature. These are due 
to the diminution of the quantity of heat generated on the sur- 
face of the sun in consequence of the interception and appropria- 
tion as gravitation by the planets, of the energy returning to the 
sun from space.—C, 
Cope’s Origin of the Fittest." —Under the title of “ Origin 
of the Fittest” Professor Cope has collected into book form the 
various essays which he has published during the last twenty 
years upon the subject of evolution. During this time Professor 
Cope has won for himself a leading position among American 
naturalists, not only as an investigator, but as a thinker. To him 
is largely due the origin and growth of what is sometimes called 
the American school of evolution, or Neo-Lamarckism. It is in 
the essays embodied in the book before us that he has advanced 
of repetition and self-quotation. Published in this form, there 
cannot fail to seem a lack of unity. The reader finds difficulty 
in discovering any obvious thread to bind the essays into one 
book, and much of the interest and suggestiveness is lost thereby. 
Professor Cope promises us in the—let us hope not distant— 
future a systematic summary of the subject. But this book must 
be taken for what it is intended,—not as a separate publication 
or a connected summary, but simply as a collection of the writings 
or. * 
In the pages of this book may be found the views of the 
American Neo-Lamarckian school; for although it contains the 
* The Origin of the Fittest. By E. D. Cope, A.M., Ph.D. 8vo, November, 1886. 
D. Appleton & Co., New York. 
