508 PROCEEDINGS OF THE WASHINGTON MEETING 



Among Professor H3^att's most important contributions to the theory 

 of organic evolution is his discovery and demonstration of the law of 

 senile characteristics, the old age characters being regarded as i)rophetic 

 of the adult characters of posterit3\ Although essentially a corollary 

 to the principle of acceleration during the culmination of a group, 

 applying it forward rather than backward, and forecasting the charac- 

 ters of undeveloped tj^pes, we find in this law of retardation during the 

 degradation and extinction of a group a boldness and originality which 

 clearly entitle it to distinct and special recognition. 



Hyatt's system of classification takes account of all stages in the de- 

 velopment of the individual, instead, as heretofore, of the adult charac- 

 ters only, and he may fairly be said to have founded a distinct school 

 of paleontology, which one of his followers has fitly called the '' Hyatt 

 school." 



Although Professor Hyatt was primarily and chiefly a paleontologist, 

 his best and most enduring work, as we have seen, was accomplished 

 along biologic rather than stratigraphic lines, and his contributions to 

 the philosophic side of the science are second in value to those of no 

 man. It may be noted in passing, however, that he also accomplished 

 important results in pure biology, and in his studies on thepolyzoa and 

 sponges, and he was one of the first to recognize sponges as a distinct 

 subkingdom of animals. In this connection also ma}^ be mentioned his 

 beautiful explanation of the spiral shells of molluscs as due to the action 

 of gravity. 



The work which was nearest to his heart at the time of his death, and 

 on which he had been engaged for several 3^ears, was the solution of cer- 

 tain problems in evolution presented by the land shells of the Hawaiian 

 islands. One of these problems is the cause of variation when, appar- 

 ently, physical conditions are essentially the same, suggesting an element 

 of spontaneity which makes the organism more or less independent of 

 the environment. He had studied exhaustive!}^ man}^ thousands of 

 these shells and had planned to visit Hawaii in the spring of 1902 to 

 study the living animals and their relations to the habitat. He looked 

 forward to the completion of this research as tlie crowning work of his 

 life ; but, incomplete as it now stands, his conception of it and his splen- 

 did enthusiasm are an inspiration to those who knew him best. 



It is a matter for congratulation that a man so devoted to original work 

 as was Professor Hyatt, a man of such unusual concentration of mind 

 and habit of philosophical thought, should have given himself so largely 

 to the cause of science teaching. He was happy in transmitting to others 

 not only the knowledge he had gained, but something of his own spirit 

 of investigation. 



