he _believes_, however, that future investigation will
prove the verity of every proposition that is advanced in this book. These
propositions have been formulated only after a twenty-years study of
biology in all of its phases.

Some of the data used in this volume have appeared in _Appleton's Popular
Science Monthly_, _Lippincott's Magazine_, _Worthington's Magazine_, _New
York Medical Record_, _Recreation_, _Atlantic Monthly_, _American
Naturalist_, _Scientific American_, _Home Magazine_, _Popular Science
News_, _Denver Medical Times_, and _North American Review_; therefore the
author tenders his thanks to the publishers of these magazines for their
kindness in allowing him to use their property in getting out this work.

"WAVELAND," OWENSBORO, KY.,
January 9, 1899.

* * * * *

CONTENTS

INTRODUCTION

CONSCIOUS AND UNCONSCIOUS MIND

PAGE
Definition of mind--The correlation of physiology, morphology, and
psychology--The presence of nerve-elements in _monera_--Conscious
and unconscious mind--Unconscious ("vegetative") mind in the
jelly-fish--Anatomy, physiology, and psychology of the jelly-fish
--The origin of conscious mind. 1

CHAPTER I

THE SENSES IN THE LOWER ANIMALS

The sense of touch--The senses of taste and smell--Actinophryans having
taste--The sense of sight--Modification of sight organs by surroundings
--Sight in Actinophryans--Blind fish sensitive to light--Blind spiders
--Blind man--Primitive eyes in _Cymothoe_--In the jelly-fish, sea-urchin,
_Alciope_, _Myrianida_--The sight organs of the snail--Power of vision
in the snail--Eyes of crayfish--Compound eyes--Vision in "whirligig
beetle"--In _Periophthalmus_--In _Onchidium_--In _Calotis_--Organs of
audition--In _Lepidoptera_--_Hymenoptera_--_Orthoptera_--_Diptera_
--_Hemiptera_--_Dyticus marginalis_--_Corydalus_--Ears of grasshopper
and cricket--Of the "red-legged locust"--Of flies--Of gnats--Auditory
vesicles of horse-fly--Ears of butterflies--Cerambyx beetle--Long-horned
beetle--_Cicindelidae_--_Carabidae_. 7

CHAPTER II

CONSCIOUS DETERMINATION

Definition--How conscious determination is evolved from the senses--The
presence of nerve-tissue in _Stentor polymorphus_--The properties of
nerve-tissue--Romanes' experiment w