For example, we may learn from our knowledge of telepathy that the superficial aspect of certain stages of psychical evolution, like the superficial aspect of certain stages of physiological evolution, may resemble mere _inhibition_, or mere _perturbation_. But the inhibition may involve latent dynamogeny, and the perturbation may mask evolution. The hypnotised subject may pass through a lethargic stage before he wakes into a state in which he has gained _community of sensation_ with the operator; somewhat as the silkworm (to use the oldest and the most suggestive of all illustrations) passes through the apparent torpor of the cocoon-stage before evolving into the moth. Again, the automatist's hand (as we shall presently see) is apt to pass through a stage of inco-ordinated movements, which might almost be taken for choreic, before it acquires the power of ready and intelligent writing. Similarly the development, for instance, of a tooth may be preceded by a stage of indefinite aching, which might be ascribed to the formation of an abscess, did not the new tooth ultimately show itself. And still more striking cases of a _perturbation which masks evolution_ might be drawn from the history of the human organism as it develops into its own maturity, or prepares for the appearance of the fresh human organism which is to succeed it. Analogy, therefore, both physiological and psychical, warns us not to conclude that any given psychosis is merely degenerative until we have examined its results closely enough to satisfy ourselves whether they tend to bring about any enlargement of human powers, to open any new inlet to the reception of objective truth. If such there prove to be, then, with whatever morbid activities the psychosis may have been intertwined, it contains indications of an evolutionary _nisus_ as well.