"Easily, I think," answered the Doctor. "All inebriating agents have a two-fold action--as I have already pointed out--first, on the circulation; and secondly, on the nervous system. There can be no doubt that the mind becomes endowed with increased energy when the circulation through the brain is moderately quickened. This has been proved by observation. The case has been reported of a person who having lost by disease a part of the skull and its investments, a corresponding portion of brain was open to inspection. In a state of dreamless sleep the brain lay motionless within the skull; but when dreams occurred, as reported by the patient, then the quantity of blood was observed to flow with increased rapidity, causing the brain to move and protrude out of the skull. When perfectly awake, and engaged in active thought, then the blood again was sent with increased force to the brain, and the protrusion was still greater. Under all circumstances, increased circulation through the brain gives rise to mental excitement, and sometimes to an unusual lucidity of ideas. It is observed in the early stages of fever, and even in the dying--and this accounts for the clearing up of the mind which sometimes occurs in the last moments of life--what is called familiarly 'the lightening before death.'" "That," observed the Clergyman, "is a very curious circumstance, which I firmly believe; and you account for this, if I understand your meaning, by explaining that the blood which no longer circulates in the extremities, which may have become cold, flows with increased impetus through the brain." "Exactly so," replied the Doctor; "and upon this very principle, the rapidity of ideas, and the pleasurable mental excitement attending that temporary state of intellectual exaltation, depends on the increased rapidity of the flow of blood through the brain; but when this becomes carried to too great an extent, and the rapidity of the current disturbs the healthy condition of the brain, then the manifestations of the mind necessarily become impaired, the ideas are no longer under the control of the reasoning faculty, and the bodily organs, usually under the dominion of the will, no longer obey its mandates. This I believe to be the true theory of mental intoxication." "But there are many circumstances," observed the host, "which may accelerate or retard this excitement."