492 HYPERTROPHY OF THE BRAIN. 



ening. This condition has been rarely seen, and I have 

 witnessed a form of induration which might be regarded as 

 condensation of the nervous tissue under the influence of 

 gradual pressure, owing to the slow development of a tumour. 

 Induration is not diagnosed during life, and belongs to the 

 incurable conditions. 



ATROPHY OF THE BRAIN. 



The brain may waste ; a portion of it may be absorbed, or 

 the whole mass may diminish in volume. The cases of partial 

 atrophy due to tumour, to the development of parasites, &c., 

 are singular, from the fact that the disease advances far 

 before any symptoms of the atrophy are noticed. The upper 

 part of the cerebral hemisphere may waste away to a great 

 extent, just as portions may be cut off without symptoms 

 of disturbance, but anything like general atrophy is asso- 

 ciated with loss of consciousness and paralysis. In man, 

 atrophy of the cerebrum is accompanied by idiotcy, and in 

 the lower animals by aberration of the instinctive faculties, 

 and sometimes by viciousness. The general atrophy may 

 be due to hydrocephalus. 



HYPERTROPHY OF THE BRAIN. 



We know nothing of hypertrophy of the brain in the lower 

 animals, though the disease has been repeatedly described 

 in the human subject. " When in these cases the skull is 

 sawn through, the upper loose portion of bone starts up as 

 if moved by a spring, and the edges of the bone remain 

 widely apart." Dr Watson says that the hypertrophied 

 and compressed brain is firmer and tougher than natural ; 

 it contains but little red blood, and sections of it are seen 

 to be unusually dry and pale. 



