“If I whip a young dog which has never been punished before, both the optical stimulus — the sight of the whip — and the tactual stimulus — producing sensations of pain — act engraphically and, what is of particular importance, the engrams produced by these simultaneous stimuli enter into a certain indissoluble relationship to each other. This relationship can be defined by stating that henceforward the application of only one stimulus will suffice to act ecphorically on the engram simultaneously produced by the other stimulus. The mere sight of the whip in the hand of its master will ecphorise in the dog the mnemic excitation of the definite sensation of pain, and produce the corresponding reaction, namely, curling of the tail, howls, and flight. We describe such engrams, where the application of the engraphic stimulus of one serves as the ecphoric stimulus of the other, as associated engrams. We may state it as a rule without exception that all simultaneously-produced engrams are associated even when the effective stimuli are of different kinds and have no relationship in respect of the cause of their appearance. Two stimuli of very different kinds and without recognisable relationship once acted upon me simultaneously — the view of Capri from Naples, and a specific smell of boiling olive oil. Ever since, a similar smell of oil unfailingly acts ecphorically on the photogenic engram of Capri.”