VIII. THE LAWS OF ORDERLY SEQUENCE OF METABOLISM, GROWTH, DEVELOPMENT, PHYSIOLOGICAL CONDITIONS, AND BEHAVIOR, OR “THE LIVING ORGANISM AND THE CHANGES WHICH TAKE PLACE IN IT” THE DYNAMIC OR PROCESS RELATIONS OF THE ANIMAL 1. General Physiology and Development. 2. A Selection of Physiological and Ecological Papers. 3. Animal Behavior as a Process. 4. A List of Selected Reviews and Bibliographies. 5. A Selection of References on Life Histories and Behavior. “Seeing, then, that in all cases we may consider the external phenomena as simply in relation, and the internal phenomena also as simply in relation; the broadest and most complete definition of Life will be--The continuous adjustment of internal relations to external relations.”--HERBERT SPENCER. “It is of the utmost importance, if we are to understand the behavior of organisms, that we think of them as dynamic--as processes, rather than as structures. The animal is something happening.”--H. S. JENNINGS (1907). Not only is the environment subject to an orderly sequence of changes, but this same law applies with equal thoroughness to the living animal itself. The animal is an agent which transforms, in “an orderly sequence,” by its processes of metabolism, both energy and substance, resulting in growth, differentiation, multiplication, and behavior. These activities take place in an orderly manner and are dependent upon both energy and substance derived from the environment. For these reasons the processes or changes in metabolism, growth, development, and behavior, _in so far as they are responses to the orderly sequence of environmental changes, are ecological problems_. The changes in behavior during the life of the animal or the development of its behavior give one of the main clues to the physiological conditions which determine some of the most characteristic forms of responses, and finally as a result of all these activities and processes of adjustment to the conditions of life, a relatively mature and adjusted condition of the struggle for existence in animals and associations may be reached, the culmination of animal harmonies. For this reason studies in modifications of behavior are of fundamental ecological importance, because they consider behavior not only as ready-made, but also in the process of making. Such considerations as these make it desirable to include some of the most valuable and suggestive books and papers which deal with those general physiological processes influencing growth, development, multiplication, and behavior, and _particularly those which aid one in realizing their order or successive changes, or “orderly sequence.”_