But not only does instinctive behaviour thus introduce important elements into the conscious situation, it is also called forth by stimuli which themselves afford not less important elements. To exclude these from any consideration of instinct, in its conscious aspect, would render the treatment of the problem so incomplete as to be wholly unsatisfactory from a psychological point of view. Can we believe that when the moor-hen dived, as it never had dived before, at the sight of the rough-haired pup, the vivid experience of that strange and disquieting intruder did not enter into, and form a prominent feature in, the conscious situation? If we are to consider the conscious aspect at all, we must try and grasp the situation as a whole. And on these grounds we may yet further broaden our conception so as to include, from the psychological point of view, not only the behaviour itself, and its effects in consciousness, but also the stimulating conditions under which it is called into play. If, then, we accept this position, and agree to use the term “instinct” for our present purpose in a comprehensive sense, we may now proceed to consider very briefly the nature of the elements which enter into the instinctive situation. First, there are the external stimuli affecting one or more of the sense organs, and thus evoking consciousness; and secondly, there are internal factors, having their source in the condition of the body, or its parts and organs. It is convenient to take these two together, so that we may see what relationship they bear to each other. Both seem to be present, and to co-operate in a great number of instinctive acts. In the behaviour connected with feeding, for example, an internal element of hunger co-operates with the external presentation of the appropriate food or prey. So, too, with the instincts concerned in the propagation of the race. Looking at the matter generally, we may regard the internal factors of the kind with which we are now dealing, as giving rise to a want or need, passing in some cases into a state of craving. In themselves such conscious states are in their inception exceedingly indefinite; for a want can only be rendered definite in experience by its appropriate satisfaction. In many cases of instinctive behaviour the indefinite want and the particular and duly related stimulus seem to lead, without prevision and by a blind impulse, to the performance of those acts which will afford the unforeseen satisfaction. And when once this satisfaction has been attained, subsequent wants or needs of like character will no longer be indefinite; nor will future behaviour of the same kind be thereafter wholly instinctive, for it can never again be prior to, or independent of, experience.