io6 TEE POPULAR SCIENCE MONTHLY. 



next to the face area evolved that for the arm. And so on, the next 

 step would be the development of the legs to run after the prey, and 

 here is the leg-center ; while, finally, the trunk-muscles are dragged 

 in to help the limbs more effectually. To my mind this idea receives 

 overwhelming support from the consideration of the fact that, the 

 higher our centers are, the more they require education ; the infant, 

 for instance, in a few days shapes its face quite correctly to produce the 

 food-inspiring yell, yet takes months or years to educate its upper 

 limbs to aid it in the same laudable enterprise. Finally, what terrible 

 probation some people pass through at the hands of dancing-masters 

 before their trunk-muscles will bend into the bow of politeness ! 



Now to return to the lower end of the fissure of Rolando, to the 

 areas for movements of the face : it was long ago pointed out by the 

 two Daxes and Professor Broca that when this portion of the brain 

 immediately in front of the face area was destroyed, the person lost 

 the power of articulate speech, or was only capable of uttering injec- 

 tions and customary "strange oaths." In fact, this small portion of 

 the left side of our brains (about one and a half square inch) is the 

 only apparatus for expressing our thoughts by articulating sounds, 

 and note particularly that it is on the left side. The corresponding 

 piece on the right side can not talk, as it were. This remarkable state 

 of things is reversed in left-handed people. In these the right hemi- 

 sphere predominates ; and so we find that, when this portion was dis- 

 eased, there followed aphasia, as it is called. While, however, the 

 right side customarily says nothing, it can be taught to do so in young 

 people, though not in the aged. 



Before leaving these motor areas, let me repeat, by way of recapit- 

 ulation, that the only truly bilaterally acting areas are those for the 

 lower facial and throat muscles. This is a most important fact, for 

 the idea has recently been propounded that both sides of the body are 

 represented in each motor region of each hemisphere. That is to say, 

 each motor area has to do with the movements of both upper limbs, 

 for example. In support of my contention that this is not in accord- 

 ance with clinical facts, let me here show you photographs of the 

 brain of a man who was unfortunate enough to suffer destruction of 

 the fibers leading from one motor area. Here you see a puncture in 

 the brain which has caused hasmorrhage beneath the fissure of Ro- 

 lando and the motor convolutions in front and behind it. 



In this transverse section of the same spot you see that the haemor- 

 rhage has plowed up the interior of the brain. Here is the cortical 

 gray matter, but its fibers leading down to the muscles are all de- 

 stroyed. Now, in examining this patient I asked him to move his left 

 arm or leg ; he was perfectly conscious, and, understanding the ques- 

 tion, made the effort, as we say, but no movement occurred. Now, if 

 both sides of the body are represented in each hemisphere, it seems to 

 me that such a case would be impossible, or at least that a little prac- 



