The Internal Senses. 693 



organs with which it had nothing in common. Wo must conceive it, 

 therefore, as being able to affect on!}- unengaged ( negative ) cells and 

 those which have been previously affected by like stimuli. 



The revival of cells already differentiated tends to intensify their dif- 

 ferentiation, and the differentiation of new cells by cognate stimuli tends 

 to extend the area of the organ. As every stimulus is more or less 

 compound, both of these results accompany the action of each of them; 

 that is, the organ is automatically strengthened and extended by its use. 

 The essential nature of the stimulus itself determines which of the or- 

 gans shall be influenced by it. Every object, therefore, which comes 

 within the scope of our observation, through the medium of an}' of the 

 senses, automatically sorts itself out and impresses the definite area, 

 which is alone susceptible to its influence; that is, the area which is al- 

 ready the seat of like impressions. We are constantly becoming aware 

 that such automatic classifications are effected, from the fact that the 

 new-comers stir up a recollection of the old, with which they are to be 

 associated. On hearing a story we often say, < ' that reminds me of so 

 and so I once heard." Our sensation of the relation between the 

 standard organ and a new impression, includes a sensation of them to- 

 gether, and occupying definite relationships to each other. Thus, we 

 come to be aware whether a thing is moral, religious, brave, kind, &c. , 

 by the consciousness of the sort of relationships it establishes with the 

 standard organs. 



Wagner says : ' ' Among the convolutions of different individuals, 

 there are remarkable differences, so that one ma}' distinguish richly con- 

 voluted and poorly convoluted brains. These relate only to more nu- 

 merous divisions, and to bendings, &c. , of the primary convolutions, 

 which retain the same number and essential position in all normal brains 

 of whatever race. The most notable differences occur in the convolu- 

 tion of the frontal lobes. There are to be found brains of adults 

 which, in this respect, resemble the brain of a seven-month's foetus, of 

 which it may truly be said that in their outward configuration, at least, 

 the}' have remained in a foetal condition. " As a rule, when the frontal 

 lobes are specialty complex in their convolutions, it is because they are 

 supported by well developed convolutions in the rest of the brain. 



While the principal fissures and convolutions of the cortex are blocked 

 out before birth, under the influence of heredity, a vast increase in their 

 growth and development takes place before maturity is reached. Their 

 growth is due to the great increase in the number of cells. It is re- 

 markable that in these added fissures no two brains are exactly alike, 

 and, more remarkable still, the two sides of the same brain differ greatly. 

 Difference of education and experience in different individuals causes 

 the different degrees of growth and increase of the various organs. 



