Address hy Professor Rice. xli 



strong foundation for the magnificent generalization of tlie con- 

 servation of energy — a generalization which the sagacious intuition 

 of Mayer and Carpenter and Le Conte at once extended beyond 

 the realm of inorganic nature to the more subtile processes of 

 vegetable and animal life. In this connection, I may be per- 

 mitted to refer to the work of some of my colleagues, with the 

 Atwater-Kosa calorimeter, which has given more complete experi- 

 mental proof than had previously been given of the conservation 

 of energy in the human body. 



But by far the greatest of the intellectual achievements of our 

 age has been the development of the idea of the unity of process 

 pervading the whole history of nature. The word which sums 

 up in itself the expression of the most characteristic and fruitful 

 intellectual life of our age is the word evolution. The latter half 

 of our century has been so dominated by that idea in all its think- 

 ing, that it may well be named the Age of Evolution. We may 

 give as the date of the beginning of the new epoch the year 1858; 

 and the Wittenberg theses of the intellectual reformation of our 

 time were the twin papers of Darwin and Wallace, wherein was 

 promulgated the theory of natural selection. 



And yet, of course, the idea of evolution was not new, when 

 these papers were presented to the Linnsean Society. Consciously 

 or unconsciously, the aim of science at all times must have been 

 to bring events that seemed isolated into a continuous develop- 

 ment. To exclude the idea of evolution from any class of phe- 

 nomena is to exclude that class of phenomena from the realm of 

 science. In the former half of our century, evolutionary concep- 

 tions of the history of inorganic nature had become pretty well 

 established. The nebular hypothesis was obviously a theory of 

 planetary evolution. The Lyellian geology, which took the place 

 of the catastrophism of the last century, was the conception of 

 evolution applied to the physical history of the earth. 



Nor had there been wanting anticipations of evolution within 

 the realm of biology. The author of that sublime Hebrew psalm 

 of creation, preserved to us as the first chapter of Genesis, was in 

 his way a good deal of an evolutionist. "Let the earth bring 

 forth," —"let the waters bring forth," — are words that point to a 

 process of growth rather than to a process of manufacture in the 

 origination of living beings. In crude and vague forms, the idea 



