ANCIENT TYPES OF MAN _Illustrated_ "The kind of book that only a master of his subject could write. It must interest every thinking person."_--British Medical Journal._ PROF. FREDERICK CZAPEK CHEMICAL PHENOMENA IN LIFE Discusses in clear, concise terms the great question--"Can life be explained by physics and chemistry?" It deals with the life-processes of plants, the molecular structure of protoplasm, organic synthesis in the cell, the nature of ferments, and the subject of inheritance. SIR A. TILDEN, F.R.S. THE ELEMENTS Speculations as to their Nature and Origin _Diagrams, &c._ Points to the conclusion that the elements resulted from a change in some primal essence, and discusses "whether all may not be suffering a slow waste, which, in the long run, must lead back to the primal chaos." SIR WILLIAM RAMSAY, F.R.S. ELEMENTS AND ELECTRONS _Diagrams_ The electron--"the atom of electricity"--is shown to be separable from matter, and to be capable under certain circumstances of independent existence. The book shows that the electron must be regarded as a kind of "element" itself, with much stronger claims to "elementary" or undecomposable characters than the bodies hitherto ranked as elements. Transcriber's Notes: Passages in italics are indicated by _italics_. Superscripted characters are indicated by {superscript}. The original text includes symbols which are represented by [Symbol] in this text version. End of Project Gutenberg's Are the Planets Inhabited?, by E. Walter Maunder