Though thus active in pushing forward the limit of fact and theory in the domain of pure science, Professor Brooks has not shirked the duty that falls to every member of society, but has labored earnestly to build a sound basis for immediate practical application of zoölogical research. In 1876 he organized a summer zoölogical laboratory for teachers and others in Cleveland, with the co-operation of two other young Clevelanders--A. H. Tuttle, now Professor of Biology in the University of Virginia, and I. B. Comstock, Professor of Geology in the University of Arizona. Identifying himself with the interests of the community in which he had cast his lot, he interested himself in the establishment of such educational influences as that of a public aquarium, and it was through no fault of the sower that the seed laboriously sown fell upon stony ground. In the winter of 1880 he gave a course of lectures and of laboratory work for teachers in the schools of Baltimore. Again, his early studies of the development of the oyster (for which he was awarded the medal of the Société d'Acclimatisation of Paris in 1883), his discovery that the American oyster could be reared like fish from artificially fertilized eggs, since he found it to have a different life history from its European fellow, led him to realize the greater possibilities that awaited our oyster industries when they should be based upon scientific fact. Living amid a population dependent to no small extent upon these industries, Professor Brooks threw himself with enthusiasm into the problem of warding off the ruin that comes to every enterprise expanding faster than its capital is replenished, and eagerly sought the means to magnify without deterioration so important a factor in the existence of the Commonwealth. As chairman of the Oyster Commission appointed by the General Assembly of Maryland in 1882, he drew up the long, detailed, and well-illustrated report, issued in 1884, which set forth the condition of the oyster beds in the Chesapeake Bay and their deterioration from overwork, and suggested a legislative remedy in the form of a bill designed to remove this industry from that primitive, barbaric stage in which our communal ownership of migrant birds and fish still remains, and to place it upon the secure basis of personal ownership underlying other live-stock business. But it is difficult to change the customs of centuries' standing, and prophets rarely see the fulfillment of their predictions. Many lectures and the issue of a popular book--The Oyster, 1891--were necessary labors assumed by Professor Brooks before the public mind was educated to some appreciation of the nature of the problem, and the fruits of his labors are yet to be matured and gathered.