Produced by Simon Gardner, Bryan Ness and the Online Distributed Proofreading Team at http://www.pgdp.net (This book was produced from scanned images of public domain material from the Google Print project.) Transcriber's Notes In this Plain Text version, unicode characters are used: α[alpha], β[beta], γ[gamma], λ[lambda], ν[nu], π[pi] & υ[upsilon], ♂[male], ♀[female] and ⇆ [left arrow over right arrow]. Italic typeface has been represented by the use of _underscores_. Small capital typeface has been represented by the use of ALL CAPITALS. Superscript characters are indicated by caret and braces, e.g. 10^{-8} ("ten to the power of minus eight"). Subscript characters are indicated by underscore and braces, e.g. H_{2}O. Uncommon forms for chemical names have been retained where they occur in the text, e.g. "atropin" for "atropine"; "asparagin" for "asparagine", etc. The spellings of "Sidot blend" and "Sidot blende" are used interchangeably in the text. Some inconsistencies in formatting and punctuation have been retained from the original. "PH" or P_{H} (P subscript H) is retained as used in the text for the scale of alkali-acidity where the more familiar modern usage is "pH". Molar concentrations are indicated in various ways (lower case m, italic lower case m, small capital M). Changes to the text have been made only in the case of obvious spelling or type-setting errors. These are listed at the end of the book. * * * * * MONOGRAPHS ON EXPERIMENTAL BIOLOGY EDITED BY JACQUES LOEB, Rockefeller Institute T. H. MORGAN, Columbia University W. J. V. OSTERHOUT, Harvard University THE NATURE OF ANIMAL LIGHT BY E. NEWTON HARVEY, Ph.D. * * * * * _MONOGRAPHS ON EXPERIMENTAL BIOLOGY_ PUBLISHED FORCED MOVEMENTS, TROPISMS, AND ANIMAL CONDUCT By JACQUES LOEB, Rockefeller Institute THE ELEMENTARY NERVOUS SYSTEM By G. H. PARKER, Harvard University THE PHYSICAL BASIS OF HEREDITY By T. H. MORGAN, Columbia University INBREEDING AND OUTBREEDING: THEIR GENETIC AND SOCIOLOGICAL SIGNIFICANCE By E. M. EAST and D. F. JONES, Bussey Institution, Harvard University THE NATURE OF ANIMAL LIGHT By E. N. HARVEY, Princeton University IN PREPARATION PURE LINE INHERITANCE By H. S. JENNINGS, Johns Hopkins University THE EXPERIMENTAL MODIFICATION OF THE PROCESS OF INHERITANCE By R. PEARL, Johns Hopkins University LOCALIZATION OF MORPHOGENETIC SUBSTANCES IN THE EGG By E. G. CONKLIN, Princeton University TISSUE CULTURE By R. G. HARRISON, Yale University PERMEABILITY AND ELECTRICAL CONDUCTIVITY OF LIVING TISSUE By W. J. V. OSTERHOUT, Harvard University THE EQUILIBRIUM BETWEEN ACIDS AND BASES IN ORGANISM AND ENVIRONMENT By L. J. HENDERSON, Harvard University