U4 AN INTRODUCTION TO SCIENCE 



is almost but not quite solved, and it is doubtful whether 

 this or any other question which the physiologist is asked 

 can ever be so answered as to leave nothing more to say. 

 As knowledge increases we see farther into the unknown, 

 and each de*cade is less notable for the questions which it 

 lays to rest than for the further questions to which the 

 process of answering gives rise. 



