We do actually think of bodily parts or organs as material structures quite apart from the consideration of their functions: it is the distinction between morphology and physiology--an altogether artificial one. An animal, for the morphologist, is a complex of skeleton, muscles, nerves, glands, and so on; and it does not matter whether it is contained in a jar of methylated spirit or is running about in a cage. For the physiologist it is “something happening”; but is it not really both things, and are not the structure and the functioning only two convenient, but arbitrary, aspects from which we consider the organism? We ought not to think of diaphragm and lungs apart from the movements of these organs, and we do not say that the first breath drawn by the newly-born mammal is an instinctive action, involving the use of inborn bodily tools--the diaphragm, lungs, etc. We ought not to think of the lips and mouth and pharynx of the young baby apart from the actions of suckling the mammæ of its mother, but usually we say that this action is an instinctive one. Where does the ordinary functioning of an organ end and its instinctive functioning begin? Are the muscular actions of the lobster when it frees its body and appendages from the carapace during the act of ecdysis instinctive ones? Most zoologists would say that they are not, any more than the movements of the maxillipedes in respiration are instinctive ones, yet they probably would not hesitate to say that the action of the “soft” lobster in creeping into a rock crevice is instinctive. Does a young child really “learn” to walk? It is more likely that the actions of walking are potential in its limbs and that they become actual when all the connections of nerve tracts and centres in its brain and spinal cord become established. What is the difference between the acquirement of the ability to walk and to write? The latter series of actions are unfamiliar combinations of nervous and muscular activities which are no part of the organisation of the young child; while the former are simply the result of the complete functional development of certain nervous and muscular apparatus.