In order thoroughly to comprehend the formation of our consciousness of the ‘Ego,’ and the presentation of the existence of a ‘non-Ego,’ we must consider a third point. All the parts, all the cells of our body, have their own separate consciousness, which accompanies every one of their excitations. These excitations are occasioned partly by the activity of nutrition, of assimilation, of the cleavage of the nucleus--that is to say, by the vital processes of the cell itself, and partly by action of the environment. The excitations which proceed from the interior, the bio-chemical and bio-mechanical processes of the cell, are continued, and endure as long as the life of the cell itself. The stimulations which are the result of the action of the environment only appear, of course, with this action, _i.e._, not continuously, but intermittently. The vital processes in the cell have direct value and significance only for the cell itself, not for the whole organism; actions of the environment may become important for the whole organism. The principal organ, the brain, acquires the habit of neglecting the excitations relating to the interior vital activity of the cell--first, because they are continuous, and we perceive distinctly only a change of state, not a state itself; and then, because the cell accomplishes its own functions by its own energy, which renders the interference of the brain useless. The brain takes notice, on the contrary, of excitations which are produced by action _ab extra_--first, because they appear with interruptions; and, secondly, because they may necessitate an adaptation of the whole organism, which could only take place through the intervention of the brain. It cannot be doubted that the brain has knowledge also of the internal excitations of the organism, and only for the reasons already stated is not, as a general rule, distinctly conscious of them. If through illness a disturbance is produced in the functions of the single cell, we at once become conscious of the processes in the cell--we feel the diseased organ, it stimulates our attention; the whole organism is uncomfortable and out of tune. It is sensations of this kind, which, in a healthy state, do not distinctly reach our consciousness, that make up the sensation of our body, our organic ‘I,’ the so-called cœnæsthesis or general sensibility.