Chap. XXIV.] PRINCIPAL PARTS OF THE BRAIN. 493 



(b.) If we look, on the other hand, to the question as 

 to wliat amount of Intellectual Power is possible where 

 one Hemisphere of the Cerebrum has been very much 

 damaged or atrophied ; there can be little doubt that, as 

 a rule, the ps}'chical powers would be found very much 

 blunted or paralyzed. This, however, is far from being 

 universally the case, for there are instances on record in 

 which, with atrophy or extensive disease of one Hemisphere, 

 the Intellectual Faculties appeared to be in their normal 

 condition. 



Preservation of any considerable Mental Power when 

 there is great damage to one Hemisphere is, however, very 

 rarely met with when the damage occurs late in life. It 

 is much more likely to be encountered when the disease or 

 damage has set in or happened in early childhood : at a 

 time, that is, when the growth and textural development 

 of the Brain is capable of undergoing considerable modi- 

 fications that may fit it for the more or less isolated 

 activity of the one Hemisphere — which, in the cases sup- 

 posed, may be almost all that is possible. Such an early 

 onset of the disease is, indeed, found by the writer to have 

 existed in many of the best authenticated cases belonging 

 to this category.* 



Perhaps the most remarkable of all the cases of this sort on 

 record is one which was observed and reported by Andral. A man, 

 who died in his twenty-eighth year, had a fall when three years 

 old, after which he continued paralyzed on the left side. The right 

 hemisphere of the brain was found to be so completely atrophied 



ness of the waldng state. In each case the sensorial regions of 

 the hemispheres would seem to be the initial or central tracts whose 

 activity is roused — in the one case, by real, and, in the other, by 

 revived, sensorial impressions. 



* " Atrophy of the Left Hemisphere." New Sydenham Soc, 

 vol xi. p. 153. Several cases are here referred to by S. Van der 

 Kolk, including the one recorded by Andral. 

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