VI CONTENTS. 



PAGE 



yielded by alimentaiy substances is transformed partly into heat 

 and partly into work Seat of combustion in the organism 

 Heating of the glands and muscles during their functions Scat 

 of calorification Intervention of the causes of cooling Animal 

 temperature Automatic regulator of animal temperature . . 19 



CHAPTER IV. 



ANIMAL MOTION. 



Motion is the most apparent characteristic of life ; it acts on 

 solids, liquids, and gases Distinction between the motions of 

 organic and animal life We shall treat of animal motion only 

 Structure of the muscles Undulating appearance of the still 

 living fibre Muscular wave Shock and myography Multi- 

 plicity of acts of contraction Intensity of contraction in its 

 relations to the frequency of muscular shocks Characteristics 

 of fibre at different points of the body 27 



CHAPTER V. 



CONTRACTION AND WORK OF THE MUSCLES. 

 The function of the nerve Speed of the nervous agent Measures 

 of time in physiology Tetanus and muscular contraction- 

 Theory of contraction Action of the muscles .... 41 



CHAPTER VI. 



OF ELECTRICITY IN ANIMALS. 



Electricity is produced in almost all organised tissues Electric cur- 

 rents of the muscles and the nerves Discharge of electric 

 fishes ; old theories ; demonstration of the electric nature of 

 tliis phenomenon Analogies between the discharge of electrical 

 apparatus and the shock of a muscle Electric tetanus Rapidity 

 of the nervous agent in the electrical nerves of the torpedo ; 

 duration of its discharge 49 



CHAPTER VII. 



ANIMAL MECHANISM. 



Of the forms under which mechanical w<>rk presents itself Ev. IT 

 machine must bo constructed with a view to the kind of work 

 which it has to perform Correspondence of the lurm >! -miM-lf 

 with the work which it accomplishes Theory of Borelli 

 Specific force of muscles of machines; they only change the 



