I'EKCEi'TlON. 45<3 



State of our existence, the operations of the mind 

 are conducted by the instrumentality of our bodily 

 organs ; and that, luiless the brain be in a healthy 

 condition, these operations become disordered, or 

 altogether cease. As the eye and the ear are the 

 instruments by which we see and hear, so the brain 

 is the material instrument by which we retrace and 

 combine ideas, and by which we remember, we 

 reason, we invent. Sudden pressure on this organ, 

 as in a stroke of apoplexy, puts a total stop to all 

 these operations of the mind. If the pressure be 

 of a nature to admit of remedy, and has not in- 

 jured the texture of the brain, recovery may take 

 place ; and immediately on the return of conscious- 

 ness, the person awakes as from a dream, having 

 no sense of the time which has elapsed since the 

 moment of the attack. All causes which disturb 

 the healthy condition of the brain, such as alcohol, 

 opium, and other narcotic drugs, or which disorder 

 more especially the circulation in that organ, such 

 as those inducing fever, or inflammation, produce 

 corresponding derangements of the intellectual 

 powers ; modifying the laws of the association of 

 ideas, introducing confusion in the perceptions, 

 irregularity in the trains of thought, or incapacity of 

 reasoning, and leading to the infinitely diversified 

 forms of mental hallucination, delirium, or insanity. 

 Even the strongest minds are subject to vicissitudes 

 arising from slighter causes, which affect the gene- 

 ral tone of the nervous system. Vain, indeed, was 

 the boast of the ancient Stoics that the human 

 mind is independent of the body, and impenetrable 

 to external influences. No mortal man, whatever 

 may be the vigour of his intellect, or the energy ol 



