PREFACE 



The writer is annually in receipt of letters from students, 

 teachers, ministers, medical men, and others, asking for in- 

 formation on topics in general biology, and for references to 

 the best reading on that subject. The increasing frequency 

 of such inquiries, and the wide range of topics covered, have 

 created the impression that an untechnical account of the 

 rise and progress of biology would be of interest to a con- 

 siderable audience. As might be surmised, the references 

 most comimonly asked for are those relating to different 

 phases of the Evolution Theory; but the fact is usually over- 

 looked by the inquirers that some knowledge of other features 

 of biological research is essential even to an intelligent com- 

 prehension of that theory. • 



In this sketch I have attempted to bring under one view 

 the broad features of biological progress, and to increase the 

 human interest by writing the story around the lives of the 

 great Leaders. The practical execution of the task resolved 

 itself largely into the question of what to omit. The number 

 of detailed researches upon which progress in biology rests 

 made rigid selection necessary, and the difficulties of separat- 

 ing the essential from the less important, and of distinguish- 

 ing between men of temporary notoriety and those of endur- 

 ing fame, have given rise to no small perplexities. 



The aim has been kept in mind to give a picture suffi- 

 ciently diagrammatic not to confuse the general reader, and 

 it is hoped that the omissions which have seemed necessar}' 

 will, in a measure, be compensated for by the clearness of 

 the picture. References to selected books and articles have 



