6 EDITOR'S PREFACE 



to record and to think, but the fine glow of the missionary spirit 

 is not with these. 



And this fine glow enabled many of these men to become great 

 teachers. To be a great teacher is in part a matter of tempera- 

 ment, though that power may lie with a silent and reserved man, 

 like Brooks, as well as with the eloquent and visibly sympathetic 

 ways of Agassiz. Some few, though teachers, lacked the teach- 

 ing spirit; Gibbs for example was a lonely thinker, unknown to 

 students and colleagues, the author of books no one in his genera- 

 tion was ready to read. 



The crowning privilege of the great teacher lies in the heredity 

 of his inspiration, his power to found a school of greatness among 

 younger men who have caught his enthusiasm and his methods. 

 Such series are well recognized in American science. I once heard 

 Agassiz say: "I lived for four years under Dr. Dollinger's roof, 

 and my scientific training goes back to him and to him alone." 

 The descendants of Agassiz are well traceable in American sci- 

 ence. There is scarcely a worker in biology and geology of the 

 older generation who was not in some degree at some time a pupil 

 of Agassiz. It is now nearly forty years since Agassiz died, and 

 the youngest of those of us who knew him are now coming also 

 to the age of sixty, the age when a man is set in his ways and can 

 learn nothing new. 



In his Autobiography, Darwin, who never spared himself, 

 deplores the fact that with increasing knowledge (and a long period 

 of nervous invalidism) his mind had suffered a partial atrophy, 

 and his interest in literature, even the best, had largely failed him. 

 From this unfortunate fact, frankly expressed, the lesson has been 

 drawn wearisomely that one should shun too much devotion to 

 science, under penalty of esthetic and spiritual barrenness. It 

 is clear from the frequent references in these biographies to artistic 

 taste and skill, that Darwin's experience was individual, and doubt- 

 less in some degree pathological. These men for the most part 

 found science a source of mental freshening. They lost no human 

 interest which they had ever possessed. In witness of this fact, 

 we see another of our great men of science, Shaler, a life-long boy, 



