CONTENTS. 



LECTURE I. 



PAGE 



Oil the Three Stages of our Ideas regarding the Union 

 of Ponderable Matter and Force in the Abiological 

 Sciences . 1 



LECTURE II. 



On the First and Second Stages of our Ideas regarding 

 the Union of Ponderable Matter and Force in the 

 Biological Sciences . . . . . .40 



LECTURE III. 



On the Third Stage of our Ideas regarding the Union 

 of Ponderable Matter and Force in the Biological 

 Sciences . . . 65 



[APPENDICES 



