14 Preface. 



observer and thinker may do something to settle 

 these disputed points, but the scantiness of materi- 

 als generally at hand and the liability to error in 

 the interpretations of facts, should make every la- 

 borer cautious in his own work and lenient towards 

 the mistakes of others. It is with a deep convic- 

 tion of the need of the hearty cooperation of the 

 cultivators of different fields of science, especially 

 of Naturalists and Mental Philosophers, in the full 

 study of man, that these Lectures are presented to 

 the public. The necessity of investigation in spe- 

 cial departments of science is readily conceded. 

 But if men must consume all their strength on one 

 specialty they should remember that excellence in 

 that is no measure of their ability to decide ques- 

 tions in other departments. But such excellence 

 in a single specialty, however restricted, is too often 

 taken by its possessor and by the community as a 

 measure of his just authority on every question he 

 chooses to decide. Broad culture as a foundation 

 for scientific attainments, respect for other sciences 

 than our own and intercourse with those who view 

 the same subjects from other stand-points than our 

 own, are absolutely essential for safe generalizations 

 in those complex sciences that relate to animal and 

 rational life. 



If these Lectures quicken the interest of any 

 in the study of nature or in a more thorough in- 



