NATURAL HISTORY MUSEUMS 39
specimens but rather to place on view particular groups of a direct teaching value. How far even the best collections do actually teach is, however, a matter of much dispute among museum directors. Some museums are trying the plan of frequently changing the exhibition col- lections, so as to offer more variety to the public. Thus the exhibition collections represent faunae, factors of distribution and of evolution, phyletic series, habitats of animals, stratigraphic series, etc. For the gathering of collections of these two kinds museums, as far as they are able, send out regular collecting expeditions; and indeed our National Museum is, to a great extent, the result of natural explorations. Both academies and museums usually maintain public lecture courses — as now do almost all learned institutions.
The work that the museums are doing in biology is mainly taxo- nomic, the study of groups, and ecologic, that of life environments. Their teaching is accomplished by short lecture courses, natural history excursions, and by exhibition of collections illustrating particular subjects.
The remainder of the work in natural history is done mainly in other institutions. Mineralogy is the branch of geology studied chiefly in universities and various technical schools. Almost all the branches of biology, except taxonomy, are taught outside of museums. Morphology and physiology are followed mainly at universities and marine labora- tories, the experimental study of evolution including inheritance at these and at special experimental stations — governmental and private, and the newer sides of biology, biochemistry, biophysics and compara- tive psychology are practically unrepresented at the museums. For experimental research as distinguished from taxonomic, in fact for the study of vital details of any kind, one goes to a laboratory rather than to a museum.
Thus, on the one hand, there is the natural-history museum. Its research presents the historical or phyletic standpoint, and tends to consider the entire adult organism without attempt at abstraction of particular qualities. There is the laboratory proper, at university or marine or fresh-water or experiment station, that digs into the inside of the animal with the microscope, that tries to trace its whole develop- ment, that attempts to reduce its processes to known physical and chemical factors. The two sets of institutions are, on the whole, sharply differentiated, their work is contrasted, one can not say a prion which has the greater importance, but in time we shall be able to de- cide which has brought the greatest treasures to human knowledge. Certain it is that the pioneer work of the taxonomist opened the way for the theory of descent, and that without such work the experimental student of evolution could hardly attack his subject. And high-class taxonomic work requires as rare judgment and intuition as is demanded in any other scientific pursuit.