Chapter II: Preface

Bioluminescence, the production of light by animals and plants, has always excited the admiration of the layman and the wonder of the scientist. It is not surprising that an enormous literature dealing with the subject has grown up. A large part of this literature, however, is made up merely of reports that a certain animal is luminous, or records of especially brilliant phosphorescence of the sea. Among those who have inquired somewhat more carefully into the nature and causes of light production may be mentioned the names of Beijerinck, R. Boyle, Dahlgren, Dubois, Ehrenberg, Krukenberg, Mangold, McDermott, Molisch, Panceri, Pflueger, Phipson, Quatrefages, Spallanzani, and Trojan. Several of these men have written comprehensive monographs on the subject.

It is not the purpose of this book to deal with every phase of bioluminescence. Volumes could be written on the evolutionary side of the problem and the structure and uses of luminous organs. These questions can only be touched upon. Neither is it my purpose to discuss the ultimate cause of the light, whether due to vibration of electrons or to other causes. That problem must be left to the physicist, although it is highly probable that a study of animal light will give important information regarding the nature of light in general, and no theory of light can be adequate which fails to take into account the extraordinary powers of luminous animals.

We shall be concerned largely with the physical characteristics of animal light and the chemical processes underlying its production. Great advances have been made since the first early guesses that the light was due to phosphorus and was a kind of oxidation. Although the problem cannot be considered as solved, it has been placed on a sound physico-chemical basis. Some material is oxidized. Exactly what this material is and why light accompanies its oxidation are the two more fundamental problems in the field of Bioluminescence. How far and with what success we have progressed toward a solution of these problems may be seen from a perusal of the following pages.

It gives me pleasure to acknowledge the kindness of Dr. W. E. Forsythe of the Nela Institute, Cleveland, Ohio, in reading and criticizing the manuscript of Chapter III, and of Professor Lyman of Harvard University for a similar review of Chapter II. I am also deeply indebted to my wife for reading the proof and to Dr. Jacques Loeb and Prof. W. J. V. Osterhout for many suggestions throughout the book. My thanks are also due to Prof. C. Ishikawa of the Agricultural College, Imperial University of Tokio, Japan, for his generous assistance in providing _Cypridina_ material. Finally I wish to acknowledge the support of the Carnegie Institution of Washington, through its director of Marine Biology, Dr. Alfred G. Mayor. Without this support much of the work described in this book could not have been accomplished.

E. N. H.

PRINCETON, N. J.,
October, 1919.

CONTENTS

CHAPTER PAGE

I. LIGHT-PRODUCING ORGANISMS 1

Early records and theories. "Shining fish and flesh." "Burning
of the sea." Distribution of luminous organisms in plant
and animal kingdoms. Secondary luminosity. False luminosity.
St. Elmo's fire. Ignis fatuus. Flashing of flowers.
Luminosity in man. Use to man of photogenic organisms.

II. LUMINESCENCE AND INCANDESCENCE 20

The complete spectrum. Radiation and temperature. "Cold
light." Thermoluminescence. Phosphorescence and fluorescence.
Triboluminescence and piezoluminescence. Crystalloluminescence.
Chemiluminescence.

III. PHYSICAL NATURE OF ANIMAL LIGHT 40

Purkinje phenomenon. Color and spectra of animal light.
Polarization. Efficiency of animal light. Infra-red radiation.
Ultra-violet radiation. Luminous efficiency and visual sensibility.
Production of radiation penetrating opaque objects.
Intensity of animal light. Summary.

IV. STRUCTURE OF LUMINOUS ORGANS 67

Photochemical and chemiphotic changes. The eye and the
luminous organ. Intracellular and extracellular luminescence.
Continuous and intermittent luminescence. Periodicity of
luminescence. Luminous bacteria. _Noctiluca_ and photogenic
granules. _Chaetopterus_ and luminous gland cells. _Cypridina._
Luminous glands. The firefly. Luminous organs (photophores)
with lenses, reflectors, opaque and color screens. Uses and
purpose of animal light.

V. THE CHEMISTRY OF LIGHT PRODUCTION, PART I 85

Boyle's and Spallanzani's experiments. Shining wood and burning
coal. Oxygen and luminescence. Carbon dioxide and
luminescence. Heat production during luminescence. Luminescence
and respiration. Water and luminescence. Phipson's
noctilucin. Luciferin and luciferase. Photogenin and photophelein.
Proluciferin. Oxyluciferin. Pyrophorin or luciferescein.
Chemiluminescent reactions. "Biozymooxyluminescence."

VI. THE CHEMISTRY OF LIGHT PRODUCTION, PART II 114

_Pyrophorus_ luciferin and luciferase. _Pholas_ luciferin and
luciferase. _Cypridina_ luciferin; stability, hydrolysis by acid
and enzymes, adsorption, precipitation, salting out, solubility,
distribution. _Cypridina_ luciferin a proteose? _Cypridina_
luciferase and properties. _Cypridina_ luciferase an albumin.
Specificity of luciferase. Action of fat solvent anaesthetics.
Action of cyanides. Oxyluciferin. Nature of oxidative reaction.

VII. DYNAMICS OF LUMINESCENCE 143

Minute amounts of material for luminescence. Reaction velocity
and chemiluminescence. Temperature and chemiluminescence.
Oxidation in steps. Concentration and bioluminescence. Temperature
and bioluminescence. Oxidation with and without
luciferase. Reaction velocity and color of bioluminescence.

* * * * *

THE NATURE OF ANIMAL LIGHT