We have to do with two processes, or two branches of a common process, going on side by side, and each contributing in its way to the total movement of organic life. In the case of the biological process or branch the material vehicle of life is the germ-plasm, a special kind of cells set apart for the transmission of hereditary types. In this there is a complex mingling and development of tendencies in accordance with laws of heredity which are as yet obscure. The social phase of the process takes place through the medium of psychical communication, the vehicle being language, in the widest sense of the word, including writing, printing, and every means for the transmission of thought. Through this, social types are propagated somewhat as biological types are believed to be in the germ-plasm. In each of these mediums there is a kind of growth, of selection, of adaptation of types to one another, and of survival of some at the expense of others. It should be our aim to see the two as organs of a common whole and to explain how they are related to each other. The best way to get this larger view, probably, is to consider the evolution of the matter and note how heredity and environment, as we see them working in man, have developed from lower forms of life. Among animals and plants the actions that enable a living being to cope with its surroundings and thus survive are secured mainly by heredity, and come into the world ready-made, as it were, with little or no need to be fashioned by a supplementary social process. Animal conduct, as broadly contrasted with human, is a system of fixed hereditary responses to fixed stimuli; the instinct is like a hand-organ which will play certain tunes whenever you turn the crank, and will play no others no matter what you do. If this predetermined reaction meets the needs of life, if the tune is in harmony with events, the life of the organism is furthered. But this can scarcely be unless the conditions of life have been nearly uniform through many generations, so that the instinctive mechanism has had time to become adjusted to them by a series of survivals and eliminations, such as is required for “natural selection.” If a newly hatched chick has come to have the instinct to pick up and swallow small objects of a certain appearance, this implies that such objects, for ages past, have on the whole proved to be digestible and supported life; if they ceased to do so the race of chickens, I suppose, would die out.