THE OLD PHRENOLOGY AND THE NEW. 247 



assumes the functions of its neighbour. Complete blindness only 

 ensues when both sight-centres are diseased. The same remark holds 

 good of the movements of the mouth and tongue in speech, these 

 being " bilateral," so that the centre of these latter movements on 

 one side may be destroyed without causing paralysis of the tongue, 

 provided the centre of the other side is uninjured. Movements of 

 the hands and feet are, on the contrary, one-sided. Destruction of 

 one centre governing these latter movements, ensures complete cessa- 

 tion of the movements on the opposite side of the body. 



Now, in aphasia or speechlessness, we merely perceive the results 

 of the destruction of the single speech-centre the left which man 

 normally uses to express his thoughts. Just as we use the right 

 hand in preference to the left in prehension, in writing, and in 

 performing all the delicate operations of our lives, and just as the 

 movements of the right hand are regulated by the left side of the 

 brain, so our faculty of articulation is also unilateral and single-handed, 

 so to speak. The memory of sounds and words forms the basis of 

 our speech "the memory of words is only the memory of certain 

 articulations" and those parts of the brain which regulate articulation 

 are also the memory-centres for speech or the result of articulation. 

 Thus, when the speech-centre is disorganised, not merely the power 

 of articulation disappears, but also the memory of words. 



But whilst the left side is that of the speech-centre, there is no 

 reason, as Dr. Ferrier remarks, apart from heredity and education, 

 why this should necessarily be so. " It is quite conceivable," Dr. 

 Ferrier holds, " that a person who has become aphasic by reason of 

 total and permanent destruction of the left speech-centre, mayreacquire 

 the faculty of speech by education of the right articulatory centres." 

 We speak with the left side of our brains, in short, not because we 

 are unable to do so with the right side, but simply because habit and 

 the law of likeness together strengthen and perpetuate the custom of 

 speaking with the left. But it may be also supposed, that as a left- 

 handed person must regulate the movements of his arms chiefly by 

 the right side of his brain, so there may exist subjects who naturally 

 use the right instead of the left speech-centre. 



Dr. Ferrier on this point remarks that "a person who has lost the 

 use of his right hand may, by education and practice, acquire with his 

 left all the cunning of his right. In such a case, the manual motor 

 centres of the right hemisphere become the centres of motor acquisi- 

 tions similar to those of the left. As regards the articulating centres, 

 the rule seems to be that they are educated, and become the organic 

 seat of volitional acquisitions on the same side as the manual (and 

 left) centres. Hence, as most people are right-handed, the education 

 of the centres of volitional movements takes place in the left hemi- 

 sphere. This is borne out by the occurrence of cases of aphasia with 



