I was able to wear the countenance of Jekyll. At all hours of the day and night, I would be taken with the premonitory shudder; above all, if I slept, or even dozed for a moment in my chair, it was always as Hyde that I awakened.
Under the strain of this continually impending doom and by the sleeplessness to which I now condemned myself, aye, even beyond what I had thought possible to man, I became, in my own person, a creature eaten up and emptied by fever, languidly weak both in body and mind, and solely occupied by one thought: the horror of my other self.
But when I slept, or when the virtue of the medicine wore off, I would leap almost without transition (for the pangs of transformation grew daily less marked) into the possession of a fancy brimming with images of terror, a soul boiling with causeless hatreds, and a body that seemed not strong enough to contain the raging energies of life.
The powers of Hyde seemed to have grown with the sickliness of Jekyll.