Page:Mind and the Brain (1907).djvu/254

 the part which belongs to it. The excitement, for instance, will be suppressed, and the cognition will be retained. Is it possible to make, or at least to imagine, such an analysis? Perhaps: for, of these two competing activities, one is variable, since it depends on the constantly changing nature of the objects which come into relation with us; the other, on the contrary, is a constant, since it expresses the contribution of our nerve substance, and, though this last is of very unstable composition, it necessarily varies much less than the series of excitants. We consequently see faintly that these two elements differ sufficiently in character for us to be able to suppose that they are separable by analysis.

But how could this analysis be made? Evidently not by chemical or physical means: we have no need here of reagents, prisms, centrifugal apparatus, permeable membranes, or anything of that kind. It will suffice to suppose that it is the consciousness itself that is the dialyser. It acts by virtue of its own laws—that is to say, by changes in intensity. Supposing that sensibility increases for the variable elements of the undulation, and becomes insensible for the constant elements. The effect will be the same as a material dissociation by chemical analysis: there will be an elimination of certain elements and the retention of others.