ACQUIRED DIFFERENCES. 7 



right eye also, commonly accompanies right-handedness, 

 though not always. The right eye and its associated 

 nerve mechanism has usually a higher functional activity 

 than the left, as those who use the telescope or microscope 

 know, as also do the rifle- and artillery-man; not only 

 the power of seeing, but that of observing appears more 

 developed in the right-sided organ. 



So far as my experience goes, the senses of touch, 

 taste, smell, and also hearing (apart from its speech 

 relations) are not one-sided. I have tested them in great 

 numbers of persons. Man is not only right-handed, the 

 lower limb participates in the right-sidedness as almost 

 any football player will testify. 



As nearly all sensory and motor nerve fibres decussate, 

 it follows that the left brain is associated with the 

 preferential use of the right side ; we should consequently 

 expect to find the left hemisphere differing slightly from 

 the right. I think I am correct in stating that, as a rule, 

 the arrangement of convolutions in the anterior lobe of 

 the left hemisphere in a well-developed brain, is more 

 complex than on the right. Moreover, there is no doubt 

 that the faculty of conveying ideas to others by phonetic, 

 visible, or written signs, has developed in man almost 

 exclusively in the third left inferior frontal convolution. 

 And not only does outgoing language such as speech or 

 writing proceed from nerve centres in the left hemisphere, 

 but also those incoming messages which we are con- 

 stantly receiving by eye and ear; the faculty of com- 

 prehending objects presented to the senses also resides 

 usually in the left hemisphere. You and I know that 

 the object I have in my hands at this moment is an 

 inkstand, because in each of us there exists a memory stored 

 in the cells of the angular and supra-marginal gyri of the 

 left brain of inkstands previously seen. Suppose the 



