258 ROUGH WAYS MADE SMOOTH. 



The general conclusion to which we seem led by the 

 observed peculiarities in the mental faculties during disease 

 is, that the mind depends greatly on the state of the body 

 for the co-ordination of its various powers. In health, these 

 are related in what may be called the normal manner. 

 Faculties capable of great development under other con- 

 ditions exist in moderate degree only, while probably, either 

 consciously or unconsciously, certain faculties are held in 

 control by others. But during illness, faculties not ordi- 

 narily used suddenly or very rapidly acquire undue pre- 

 dominance, and controlling faculties usually effective are 

 greatly weakened. Then for a while the mental capacity 

 set-ms entirely changed. Powers supposed not to exist at 

 all (for of mental faculties, as of certain other qualities, de 

 non existentibus et de non apparentibus eadem est ratio] seem 

 suddenly created, as if by a miracle. Faculties ordinarily 

 so strong as to be considered characteristic seem suddenly 

 destroyed, since they no longer produce any perceptible 

 effect. Or, as Brown-Sequard says, summing up the results 

 of a number of illustrative cases described in a course ot 

 lectures delivered in Boston : ' It would seem that the mind 

 is largely dependent on physical conditions for the exercise 

 of its faculties, and that its strength and most remarkable 

 powers, as well as its apparent weakness, are often most 

 clearly shown and recognised by some inequality of action 

 in periods of disturbed and greatly impaired health.' 



