X CONTENTS. 



LECTURE XXI. 



PAGE 



IRRITABILITY (continued] .... . 557 59 6 



The Mechanism of the Movements, 557 



Transmission of Stimuli, 582 



Biological Significance of Movements, 587 



LECTURE XXII. 



REPRODUCTION 597637 



LECTURE XXIII. 

 REPRODUCTION (continued} 638-682 



INDEX 683-710 



