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Tribune Extras Lecture and Letter Series. 



a cause -which makes the right side of the body to be se- 

 lected as the one to be used the most, aiid together -with 

 that right side of the body the left side of the brain, 

 which usually moves that right side, la increased con- 

 siderably in power and in size. There is, therefore, a 

 development given through some natural cause primi- 

 tively, but a development given to the left side. We find 

 that individuals who are left-handed make use of the right 

 side of the brain, and when they become confused when 

 they lose the faculty of expressing ideas by speech it is 

 the right side of the brain that is affected, showing the 

 connection between the development of one-half of 

 the brain in the use of one arm, and the development of 

 that same half of the brain in the faculty of expressing 

 ideas by speech. There is therefore connection be- 

 tween these two things, and on that point I shall dwell 

 a little more in a moment. There is primitively a differ- 

 ence between the two brains, and Proressor Gracciola 

 has discovered in children the second couvolutiou the 

 convolution of the left side of the brain is developed 

 quicker than the convolution oil the risrht side. That 

 may be in a measure owing to hereditary traits, I must 

 say, but at any rate as there is an evidence that there 

 is a natural tendency to make use of the right 

 arm, it is certain that a part of that 

 ability of development on the left side is due to sonae- 

 thiner natural that something natural will be found, if 

 it is examined, in the gn-ater supply of blood to that 

 part. Even parrots and birds show something very in- 

 terestinsr as regards right-handedness. Parrots perch 

 only on the right leg, or mostly only on the right leg. 

 Very few parrots out of 20 taken at random perch on 

 the left leg. according to what Dr. William Ogle ascer- 

 tained after having examined a great number of them. 

 Parrots of course are known to have something like 

 speech a parrot's speech of course. It is perfectly well 

 known that the mechanical part of speech belongs to 

 them, and it is remarkable that their left brain receives 

 also more blood by far than their right brain. 

 There is therefore a relation between all these things in 

 the development of the right side of the limbs ana the 

 amount of blood received by the left side of the brain. 

 There is another point of importance. Prof. Broadbent 

 and others have found that in the left side of the brain 

 tbe mass of gray matter is greater and there are more 

 convolutions than in the right side of the brain. 



A, REVIEW OF SOME POIXT8 DEMONSTRATED. 

 Now we come to four points of great importance for 

 Ihis lecture. They are the vital points, I may say, in tbe 

 argument I have discussed here. The first of these 

 P lints I have already spoken of. It is, that we find that 

 ngrophia is connected with the left side of the brain in 

 pc Tsons who are right-handed, and with the right side o f 

 tiiehraiuin persons who are left-hand <!. This cer- 

 tainly, is a very strong argument to show that the side 

 oi the brain which serves the motion of one side of the 

 body, that side if the side of the body the one which 

 lea 'Is, is the most important of the two that side 

 of the brain then is the one that serves chiefly to 

 the mental life in our system. Tlie rneut-il life of our 

 HVHtem, therefore, seems to be developed considerably 

 in the organ which itself seems to bo developed in a 

 jnvat measure owing to the action of will in one-half of 

 the body. There is certainly a connection between 

 these things, but that will come out more by and by 



Tiie second point Is, that in children who have not yet 

 learned to talk, or who have already learned only a 

 little, If disease comes in the lefo side of the brain, the 

 one, I repeat, which is the most rapid iu its development 



usually, if disense comes to produce atrophy, so 

 that the left side of the brain becomes useless, those 

 children then learn to talk just as well, or nearly as 

 well, as if they had no such affection, and they learn it 

 with the right side of the brain, which is the only one 

 acting. They were not born (the most of them, if not 

 all of them, if there is any exception I don't know it) of 

 parents who were left-handed, and there was 

 no reason for their being left-handed. They had the. 

 misfortune of losing the half of the brain which, 

 served usually to the mental faculties, and other men- 

 tal faculties got developed the power of speech and 

 action and they make use of the left arm then just as 

 well as any one of the right-handed people makes use of 

 the rieht arm. There is in these facts clear proof that 

 the right side of the brain can be educated to become a 

 leacicr in mental faculties as well as the left side of the 

 brain. There is a clear proof that the right side of the 

 brain can lead movements and obtain execution with 

 the left arm, just as most people who are right handed 

 obtain execution of movement with their right arm. 

 These facts, therefore, are decisive in favor of the view 

 that I have for my object in this lecture. 



The third point of importance is that with a given 

 number of individuals, out of 100 exuuiued by Dr. Win. 

 Oale, who were left-handed, four only had learned to 

 write with the left arm. They had been taught by their 

 parents, although they were left handed, to make use of 

 the right hand to write, and their writing with the left 

 arm was very clumsy, the author states. la one of the 

 cases ho had to hear what the patient had to say; the 

 patient being paralyzed in the left hand he could not 

 have the proof; butiu the others he had the proof, and 

 could see. Therefore, the left side of the brain, even in 

 persons who are left handed naturally ev<?u in persons 

 who make use chiefly of the right side of the brain tiie 

 leftside can be educated so as to produce a very gooi 

 handwriting instead, and better than tha writing by the 

 left arm. 



The fourth point of importance is one on which I shall 

 not dwell, as it implies a knowledge of medicine that 

 you have not. but I shall state it in only a few words. It 

 is exceedingly rare that the leg is affected to the saiuj 

 degree by paralysis as the arm, and the leg as you well 

 know, is not a part which we develop as much iu its 

 movements as we do develop the riffht arm. If a patient 

 is struck with paralysis, for instance, on the right side 

 of the body, owing to a disease of the left side of the 

 brain, he will lose more, if he does lose movement at all 

 he will lose more of it in the right arm which he has 

 been accustomed to train than in the right leg. B'lt, I 

 repeat, that that argument cannot be understood well 

 except by medical men. I pass it over therefore. 



There is no reason whatever to object to one teaching 

 children to make use of the two sides of the body. If 

 you have been convinced by the arguments I have given 

 that wo have two brains, it is clear that wo ouirht to de- 

 velop both of them, and I can say, at any rate, as much 

 ae this, there is a chance I would not say more, but at 

 least I can sav there is a chance that if we develop the 

 movements of the two sides of the body, the two arms 

 ami the two legs, one just as much as tho other, there is 

 a chance tint the two sides of tho brain them will bo 

 developed as regards the mental faculties, one as much 

 as the other. 



HOW TO DEVELOP BOTH SIDES OF THE BRAIN. 



The facts that I have brought forward, the last espe- 

 ciallywhat I have called the four points of importance, 

 and particularly the three first, show that there is a con- 



