^4:6 Sir James Grichton- Browne [May 3, 



are such exact duplicates that either of them will do for speech, since 

 extensive damage in the left hemisphere destroys speech altogether. 



Confining our attention now to right-handed human beings, we 

 find that the anatomical substrata for the nervous processes, animating 

 and regulating the highly special movements of the articulatory 

 muscles in voluntary speech, are localised in the left hemisphere. 

 How came they there ? Bear in mind that the muscles engaged in 

 speech, all except those of the tongue and lips, are bilaterally co- 

 ordinated and act simultaneously on the two sides. You cannot 

 breathe with one lung, leaving the other at rest ; you cannot throw 

 one vocal cord into vibration without at the same time vibrating the 

 other ; and it is impossible, therefore, that the preferential use of the 

 left hemisphere in speech can have been induced by any educational 

 efforts or lop-sided use of the vocal apparatus. Here you have one- 

 sidedness in the brain, assuredly not due to use and wont or to any 

 acquired habit or mechanical advantage. But one-sidedness, our 

 ambidextral friends tell us, is disastrous in its consequences, and they 

 must of course desire to correct it and restore symmetry to the 

 distorted brain — thus, in then- familiar formula, " doubling our 

 brain-power " — think of that ! — doubling the flow of speech in these 

 loquacious times! Well, I should be glad to know how they propose 

 to set about it, by what ingenious exercises they will confer upon the 

 right hemisphere a power of voluntary speech equivalent to that 

 possessed by the left. 



But the hand and arm centres are intimately linked with the 

 speech centres in the brain ; they lie close together and are much 

 associated in action. In disease they rise and fall together : and as it 

 is estabhshed that there is a preferential use of the left hemisphere in 

 voluntary speech, is it only logical to infer that the preferential use 

 of the right hand and arm in voluntary movements is due also to the 

 leading part taken by that hemisphere ? 



No one will have the temerity to suggest that it is artificially 

 acquired right-handedness that has dragged the voluntary speech 

 centre to the left side. If there has been any dragging, it is speech 

 that has dragged right-handedness after it, for speech begins before 

 and is generally in advance of manual dexterity, and it is only rational 

 to ascribe right-handedness and the emission of voluntary speech by 

 the left hemisphere to a common cause. 



That common cause is the constitution of the brain, a constitution 

 which has differentiated the functional activities of its two halves, 

 and as the greatest living pioneer in neurology. Dr. Hughlings 

 Jackson, has maintained, made the left hemisphere more voluntary 

 and the right hemisphere more automatic. The right-banded man 

 who is aphasic, is paralysed on the right side, and has lost speech, 

 but not altogether. What sort of speech is it he has lost ? The 

 voluntary. He cannot propositionise, and that is speech, for a 

 mere succession of words embodying no meaning is not speech but 



