It is not very certain, _pace_ Kröner, that _all_ internal sensations are caused by chemical action, under one or other of the forms we have mentioned, and that their vague localisation is due to this cause alone, and not, as generally admitted, by their arising in organs incapable of movement. Thus tickling, giddiness, the muscular sensations (which Kröner and Beaunis include in this group) appear to depend on mechanical excitations rather than on chemical causes. At any rate, one cannot deny that the internal fundamental sensations—connected with nutrition and its immediate conditions, with fatigue and sleep, both of which result from a poisoning of the muscles and the nervous centres, with sexual life—are due to chemically caused excitations. This granted, we may go one step further in the track of James and Lange, and say that the emotions depend not only on physiological conditions, but still more intimately on the chemical action going on in the tissues and fluids of the organism. In support of this extreme condition of the genesis of the emotions, we can only offer some fragmentary remarks, which, however, show how closely they depend on the variations of the intra-organic environment. 1. We have, in the first place, the group of exciting, tonic, depressing, toxic substances: wine and the various alcoholic beverages, haschisch, opium, coca, the aphrodisiacs, etc. Although they are artificial products, introduced from without, not engendered in and by the organism, we know how far they modify the interior environment, and consequently the temper, character, intensity, and direction of the passions.