_The Two Kinds of Phenomena of Vitality._—Another point on which Claude Bernard is right and his opponent is wrong is not less fundamental. What are we to understand by functional phenomena? This is the very point at issue. Now, in the mind of physiologists, this expression has a perfectly definite meaning. It is not so with Le Dantec. Physiologists who have studied animals rather high in organization—in which the differentiation of phenomena enables us to grasp the fundamental distinction—have readily recognized that the phenomena of living beings are divided into two categories. There are some which are intermittent, alternative, which take place, or grow stronger at certain moments, but which cannot be continuous—they are the _functional acts_; there are others in which this characteristic of explosives, energetic expenditure and intermittence, do not appear—they are, in general, the _nutritive acts_. The muscle which contracts shows functional activity. It has an activity and a repose. During this apparent repose we must not say that it is dead; it has a life, but that life is obscure as far as the salient fact of functional movement is concerned. The salivary gland which throws up waves of saliva when the food is introduced and masticated in the mouth, or when the chord of the tympanum is at work, is in a state of functional activity; this is the salient phenomenon. But before, though nothing, absolutely nothing, was flowing through the glandular canal, yet the gland was not reduced to the condition of a dead organ: it was living a more obscure, a less evident life. The microscopical researches of Kühne, Lea, and Langley, now universally verified, show us that during this time of apparent repose the cells were loading up their granulations and getting ready the materials of secretion, as just now the muscle at rest was accumulating glycogen and the reserve-stuff which are to be expended and destroyed in contraction. Similarly, with regard to the functional activity of the other glands, of the brain, etc. Claude Bernard was, therefore, perfectly right, when he took as his model the chemists who distinguished between exothermic and endothermic reactions, and who classed the phenomena of life into two great divisions: those of functional activity, and those of functional repose. 1st. _The phenomena of functional activity_ “are those which ‘leap to the eyes,’ and by which we are inclined to characterize life. They are conditioned by the effects of wear and tear, of chemical simplication, and of the organic destruction which liberates energy.” And it must be so, because these functional manifestations expend energy. These phenomena, which are the most obvious, are also the least specific phenomena of vitality. They form part of the general phenomenality.