A CLASSIFICATION OF FEELINGS. 335 tion a diagram in three dimensions. The most general and least differentiated forms are represented by the stem of the tree, and the more elaborate and special forms by the suc- cessively diminishing branches. Such a diagram represents accurately the classification of feelings according to the prin- ciple of evolution. The other principle of division that according to the way in which the action is begun runs, as I have said, through every branch of feeling that is consti- tuted on any other principle, but it does not necessarily destroy the other mode of classification. It may be repre- sented on our diagram by the difference between the bark and the wood a difference that is perceptible no less in the extremest branches than in the trunk, a difference that permeates throughout and yet leaves the other method of division absolutely unaffected. The analogy may be stretched much further without breaking. For just as the arborescent form is peculiar to the tree, so the division of interactions according to the principle of evolution is peculiar to the interactions between organisms and their environments ; and as the division between cortex and interior is common to the tree and all other bodies that are acted on from without, so the division between interactions that are inter- nally initiated and those that are externally initiated is common to all interactions whatever. The parallel may be earned even further. The description of the tree is not completed by the consideration of the parts that are above ground only. There yet remains the root, a part that rami- fies in a different direction and in a different manner, and is not open to direct observation. Similarly there is a body of feelings those constituting the Ccenaesthesis, or the Visceral or Organic Sensations which correspond w^th interactions occurring within the organism, and these interactions are not open to direct observation, are connected with the other interactions and are yet distinct from them, and are divisible upon a different method. There is yet a third general principle in accordance with which feelings may be divided. This is the directness or indirectness of their correspondence with interaction, and, in the latter case, the degree of remoteness from direct cor- respondence. Feelings which correspond directly with an interaction between the organism and its environment are termed Sensations ; those which correspond indirectly are termed Emotions ; and when the remoteness from direct correspondence is great, the feeling is in some cases termed a Sentiment. When the correspondence is indirect it would usually be correct to say that the feeling corresponds with a
