330 CASTLE-BUILDING. 



Effect of edu- one of the chief results is that it exercises us in the habit of 

 cation. thinking of one thing at a time, of thinking therefore with- 



out confusion, and of arriving at conclusions with precision and decision. 

 And these considerations should also, in Dr.Wigan's view, be our chief 

 guide in the cure of insanity, doing all in our power to invigorate the ac- 

 tion of the healthy hemisphere, and enable it to subdue the insubordina- 

 tion of the diseased one. If both hemispheres are diseased, the case is 

 almost hopeless. 



Of the independent and yet complete action of each of the cerebral hem- 

 Perfect action i s P neres we ^ ave abundant and interesting proof. Mental 

 of a single operations can be carried on in a profoundly diseased state of 

 hemisphere. Qne Q f fi^Q organs, as multitudes of well-authenticated cases 

 attest nay, even when the lesion has gone so far as to amount to an 

 absolute and entire disorganization of one of the hemispheres. Similar 

 evidence is also furnished by those interesting cases in which, by accident, 

 as by gunshot wound, destruction of one side has occurred. 



Even in a state of health we have numerous examples of this inde- 

 Intermixed ac P en ^ ent action of each hemisphere. While engaged in ordi- 

 tion of the two nary pursuits which imply a continued mental occupation, 

 hemispheres. we afe occas i ona ]iy troubled with suggestions of a different 

 kind. A strain of music, or even a few notes, may be perpetually ob- 

 truding, and such an occurrence we could scarcely explain save upon the 

 principle of the separate action of these organs, the one interfering with 

 the other. That precision which we have remarked as arising from the 

 conjoint use of two eyes and two ears is doubtless also attained where 

 the two hemispheres are acting in unison. We can, moreover, volunta- 

 rily permit one to rest while the other continues its duty, as we can vol- 

 untarily make use of one eye, disregarding the indications of the other ; 

 but where it is necessary to execute a critical comparison or arrive at an 

 accurate judgment of things, both hemispheres are brought into action, 

 as are both eyes when we intently consider an object. 



Among other phenomena, Dr. Wigan calls attention to the operation 

 Castle- of castle-building, as it is designated, as illustrating the volunta- 

 buiidmg. ry manner i n w hich we permit one hemisphere to act, presenting 

 fanciful delusions ; the other, as it were, watching with satisfaction the 

 operation, and in this respect lending itself to it. Not that for a moment 

 we suppose there is any truth in the ideas suggested, and in this the 

 phenomenon differs essentially from that of dreaming, in which it never 

 occurs to us that the scenes and actions are unsubstantial. 



Still more strikingly do those singular cases, which from time to time 

 Double or ai- P resent themselves to the physician, of double or alternate 

 ternate con- consciousness, illustrate this isolated function of the hemi- 

 spheres. In some of these, which have been carefully ob- 



