to have become, or to be in process of becoming, of more importance than the emotion which had given birth to it, the essence seemed merged into the form, the book had become its binding. I suggest that this may be sometimes actually the case in nature, that a movement, or a note, or series of notes, may become itself so all-absorbing as to demand the whole consciousness of the bird who, in performing it, forgets the why and the wherefore of the performance. Let this process once commence, and certain movements—antics—performed at first with a definite object, might be gone through at last for themselves alone, the object having become now merely to perform them. In this case, we should have a pure antic or display, the reason of it being unobvious and its origin a puzzle. Such a principle, if it exists, might, perhaps, be called the "law of the formalisation of actions once purposive" (which sounds learned enough), and perhaps traces of it may be seen amongst ourselves. What, for instance, are our civilised dances except movements which have become quite formal and meaningless, but which once, as in the war-dance of the savage, had an intense significance? The analogy is not quite perfect, unless we could show that actual war, for instance, had sometimes passed into a dance. Whether this has ever been the case with man I do not know, but I believe that it may have actually happened with some birds, for which idea I will further on adduce my, perhaps, somewhat slender evidence. But, coming back to the oyster-catchers, I can understand that under such a law as this, the actions of the two male birds in regard to the female might gradually get to be
