CONTENTS. 



INTRODUCTION. 



GENERAL REMARKS ON THE INFLUENCE OF PHYSICAL AGENTS ON ORGANIZATION AND LIFE. 



Object of the Work stated. Connexion of Organization with the Imponderable Principles. General Laws 

 direct all Astronomical Occurrences and Physical Events. Transitory Nature of all Combinations, and 

 especially those which are Organized. Time is an Element of Life. Inorganic Changes are brought about 

 by Physical Laws, as also is the Extinction of Living Races. Influence of Climate on the Distribution 

 and Character of Animals and Plants. Relations between Animated Forms and the Atmosphere. Influ- 

 ence of Currents in the Air and in the Sea. Gradual Emancipation of the Higher Races from the Direct 

 Action of External Agents ..... ..... . Page 1 



CHAPTER I. 



ON THE ACTION OF THE SUNBEAMS IN PRODUCING ORGANIZED BODIES. 



The Growth of Conferva? in Water. Production of Green Matter by Spun Glass and Inorganic Bodies. 

 It requires a Sporule, Cell, or Objective Germ. Mode of Diffusion of Gases into Water. Influence of 

 Temperature on the Process. Action of the Sun's Rays on these Gases. Two Atmospheres around the 

 Earth. Sources of Supply of the expended Gases. 



Application of these Principles to the Production of Chlorophyl in Leaves. The Digestion of Plants . 15 



CHAPTER II. 



ON THE MECHANICAL CAUSE OF THE FLOW OF THE SAP IN PLANTS. IT IS DUE TO THE CARBONIZATION 

 OF WATER IN THE LEAVES BY THE LIGHT OF THE SUN. 



The Flow of Sap and Circulation of Blood are probably due to the same Physical Cause. Amount of Water 

 circulating in Plants. Botanical Theory of the Flow of Sap fails for the descending Sap. 



Capillary Attraction described. Elevation or Depression of Liquids depends on their wetting or not wetting 

 the Tube. No Flow in an ordinary Capillary Tube. Conditions for producing a Flow such as Evapo- 

 ration, Decomposition, and Solution. Endosmosis produced on these Principles by Solution. Dutrochet's 

 Experiments. Explanation of them. General Law of these Movements. Force with which they take 

 place. Capillary Attraction due to Electricity. 



Application of these Principles to the Ascent of the Sap. Exhausting Action of the Leaves. Cause of the 



Descent of the Sap. 

 / The Light of the Sun is the Cause of the Flow of the Sap both in its Ascent and Descent . . .22 



CHAPTER III. 



ON THE MECHANICAL CAUSE OF THE CIRCULATION OF THE BLOOD. 



7 Ancient Theory. Description of the Systemic, Pulmonary, and Portal Circulation. General Law of Move- 

 ment. Capillary Relations of Arterial and Venous Blood to the Tissues. The Systemic Circulation is 

 due to the Deoxydation of Arterial Blood, and its Direction is therefore from the Artery to the Vein. 

 Pulmonary Circulation. Capillary Relations of Arterial and Venous Blood to Atmospheric Oxygen. Pul- 

 monary Circulation is due to the Oxydation of Venous Blood, and its Direction is therefore from the Venous 

 to the Arterial Side. Uses and Action of the Heart. 

 Portal Circulation. Capillary Relations of Arterial, Portal, and Venous Blood to the Liver. Three Sources 



of Force in conducting the Portal Circulation. 

 Action in Asphyxia. Case of obstructed Trachea 33 



CHAPTER IV. 



ON THE PHYSICAL CONSTITUTION OF THE SUNBEAMS AND ON THE PRISMATIC SPECTRUM. 



Modes of isolating the Coloured Rays. Newton's Prismatic Spectrum. Theory of the Colours of Light. 

 Illuminating Calorific and Chemical Powers of the Spectrum. Newton's Processes for purifying the 

 Spectrum. Fixed Lines. Melloni's Experiments on the Distribution of Heat. Physical Independence 

 of Heat. Herschel's Experiments on the Thermic Spectrum. Chemical Action of die different Regions 

 of the Spectrum on a Daguerreotype Plate. Chemical Action on other Bodies . . . .41 



CHAPTER V. 



ON THE INTERFERENCE SPECTRUM. 



Defects of the Prismatic Spectrum. Mode of forming the Interference Spectrum. Its Peculiarities. The 

 Distribution of the Colours, and Law of their Intensities. Reflected Interference Spectrum. Its Fixed 

 Lines. Wave-lengths of the Seven Great Rays. 



