EDUCATION AND CO-ORDINATION OF FUNCTION. 11 



I have at the present moment at the Royal Country Hospital 

 for Children, at Heswall, half a dozen cases of an infective 

 disease of the lungs giving rise to its fibrosis and contraction, 

 and in every one of them the left lung is alone involved. 



It is difficult to explain this greater vitality and strength 

 of the right side. Some say it is due to its having a more direct 

 blood supply — others that it is a purely hereditary matter, owing 

 to the greater use of the right arm through long generations 

 The fortunate thing is that there is uniformity in the difference, 

 otherwise it would lead to a great deal of inconvenience in the 

 way of using tools, and in education in the technical arts. 



I have said that the blood supply to the right limbs is 

 more direct than it is to the left, but it has to be remembered 

 that the supply to the right side of the brain is also more direct 

 than it is to the left side, which rather annuls that theory. 

 Whatever may be the explanation, it is an interesting fact 

 which may possibly have a bearing upon certain abnormalities 

 of co-ordination. By way of illustrating this, I show you a 

 left-handed boy who has a very bad stammer, and one specu- 

 lates as to whether this marked inco-ordination may be related 

 in some way to the left-sided cerebral speech centres being 

 unbalanced through the stronger right-sided development in the 

 brain. You will observe how, when this boy speaks, there are 

 jerking movements of the right arm and leg indicating an upset 

 of other motor centres besides those of speech. 

 Illustrative case shown : — 



W. M. — Example of bad stammering in a left-handed boy. Note how 

 his right side twitches when he speaks, indicating a complete want of 

 co-ordinated control, as thongh his energy expended in overcoming the want 

 of balance all comes from the left motor centres. Speculate whether 

 stammering in right-handed people may not be due to some altered co- 

 ordinative relationships between the two sides of the brain. This is probably 

 due to a structural defect and is quite often hereditary. 



Left-handedness varies greatly in degree. Of the boys at 

 Grafton Street Industrial School about G per cent, are affected, 

 some pronouncedly so, others being merely ambidextrous. 



