That the modern physician must have a thorough knowledge of biology has become more and more apparent. He has to deal with life, and life thus far at least cannot be rendered into mere mechanical, physical or chemical factors. The activities of the human machine have much that must be studied from the basis of organic nature. If we do not know all the factors or forces of life we do know that there is a complex or combination of forces radically different from any single force of inorganic nature. Chemical affinity, physical attraction and repulsion, mechanical forces may furnish many aids, but the study of life activities must go still further. To do this we must recognize the laws of organic life, the forces of growth and nutrition, of reproduction, of evolution, in fact a host of forces which have no counterpart in the inorganic world. Modern agriculture and horticulture are so dependent on the principles of biology that to dissociate them does violence to thought. Indeed this relation has existed through all recorded history, but in no period has the utility of biologic laws been so intimately blended with all the processes of cultivation. The determination of the zones of greatest productivity for different crops, their soil requirements, the introduction and acclimatization of species belonging to other faunal or floral regions, the essentials of animal and plant nutrition, the control of disease or abatement of noxious forms of plant or animal, all these and more are embraced in the service of biologic science to agriculture in its various forms and thus to human interests. Among special cases cited, but which cannot be printed here in detail, were various plant diseases, and particularly various insect pests, and the discoveries which have brought them more or less under control. Aside from the sources of food supply, which come under the general term of agriculture, we derive many articles of diet from sources dependent on animal or plant life. The various fishery industries and oyster culture which have been so wonderfully promoted by biological investigations are excellent examples of the service of science to mankind. Game laws for the protection of certain forms of life of utility to man and the possible sources of food from various animals or plants not yet utilized may be mentioned here. Clothing comes in for its share, as in the methods for protection of silkworms, the saving of fur seals and other fur-bearing animals from extinction, and the use of various fibre plants. The successful growth of sponges, of pearls and many other articles of domestic comfort or ornament are connected in one way or another with biological problems, and their fullest development dependent on rational measures possible when the biological conditions are known.