But, while sailing under the old colors and apparently by the old charts, it is quite possible that the association is, insensibly to itself, undergoing modification more or less important. Such an experience is unavoidable in all human institutions, at least in those that retain their vitality in state, society, or church. The fifty years that cover the life of the association are unquestionably the most important, so far as the growth of science is concerned, in the history of the race. Within this period every science has been recast and rewritten, and divisions and subdivisions of the old units have gone forward and are still in progress. Of every one of these sciences the boundaries have been so enormously extended that even the _dream_ of universal knowledge on the part of any man has gone by, never to return. Leibnitz, it has been said, was the last of the intellectual giants of old who mastered all that was knowable in his day. Alexander von Humboldt could almost claim the same for the knowledge of Nature that was attainable in the first quarter of our century. But since the application of the compound microscope to the study of Nature and the subdivisions of the sciences that have resulted therefrom, and especially since the extension of the method of science to all the branches of anthropology, as language, history, institutions, the task of mastering all that is known is seen to be altogether too great for finite powers and span-long lives. It might well be, therefore, in view of the amazing changes that have taken place in the entire field covered by the association, that it should have outgrown the aims and ambitions of its early days. The fact that it continues to use the identical statement of its objects with which it began its work, while it does not definitely settle the question, affords at least presumptive evidence that no such change has taken place. How, then, do the objects originally recognized by the association as its _raison d'être_ correspond to the needs of our own time? 1. Is the _social_ feature of the association, to which the first place was assigned by the founders, whether by design or not, worthy of preservation by us? In other words, is it as important "to promote intercourse between those who are cultivating science in America" at the close of the nineteenth century as it was at the middle of the century--the need that was responded to by the formation of the American Association for the Advancement of Science? While revolutionary changes have taken place in the country at large during this period in modes of travel, facilities for acquiring education, and the diffusion of intelligence, it would be hard to show why the need in this field should be in any respect less urgent. There is a far larger number of people who are cultivating science, and there are many more branches of science to be cultivated.