1 68 The Smithsonian Institution 



v. 



IT would be interesting to dwell upon the details of his 

 work, but his life was so full of interests that it is only by 

 careful condensation that even an adequate outline of its 

 eventful features can be presented in this volume. 



There were several distinct activities in his career, dis- 

 tributed somewhat as follows: (i) a period of twenty-six 

 years (1843-69) devoted to laborious investigation of the 

 vertebrate fauna of North America; (2) forty years (i84O-'8o) 

 of continuous contribution to scientific literature, of which at 

 least ten were devoted to scientific editorship ; (3) four years 

 (1846-50) devoted to educational work; (4) forty-one years 

 (1846-87) devoted to the encouragement and promotion of 

 scientific enterprises, and the development of new workers 

 among the young men with whom he was brought into con- 

 tact; (5) thirty-seven years (i85O-'87) devoted to adminis- 

 trative work as an officer of the Smithsonian Institution and 

 in charge of the scientific collections of the government 

 twenty-eight years (i85O-'78) its principal executive officer 

 and nine years (i878-'87) the Secretary and responsible 

 head of the Institution; (6) sixteen years (i87i-'87) as head 

 of the United States Fish Commission, a philanthropic labor 

 for the increase of the food supply of the world, and inciden- 

 tally for the promotion of the interests of biological and phys- 

 ical investigation. 



VI. 



THE published list of his writings contains over one thousand 

 titles. Although very many of these are brief notices and 

 critical reviews, and a considerable number are reports and 

 other official publications, there still remain two hundred 

 which are formal contributions to scientific literature. 



