726 THE POPULAR SCIENCE MONTHLY. 



the rapidity of the association processes can be altered by the use 

 of certain drugs. Thus alcoholic beverages make the sensory 

 perceptions and the jjrocess of thought slower than normal. 

 They increase the rapidity of motor acts for a short time, but 

 finally retard these, too. Tea has just the opposite effect, making 

 sensations and intellectual acts more rapid, while it delays the 

 motor actions. Morphine has at first much the same effect as 

 tea, but soon after it delays all mental acts. 



I have noticed that one of the early signs of beginning disease 

 in the brain is a decided lengthening in the processes of associa- 

 tion, even where none of these processes are absolutely suspended. 



The number of associations permanently established with any 

 given idea has been made the subject of tests, and it has been said 

 that it is a better measure of the mental capacity of an individual 

 to ascertain the number of associations which he possesses with 

 any given subject than to require him to pass an examination 

 upon his knowledge of the subject. 



Among the curiosities of thought we may mention some queer 

 disturbances in these processes of association. We may find that 

 association tracts are apparently blocked so that a perception 

 which should call up a certain concept fails to do so. 



I have seen a man look at his own son and yet fail to recognize 

 him that is, the perception of the face no longer resulted in the 

 quick spreading outward over a thousand associated tracts to 

 other parts of the brain of impulses calculated to call up the nu- 

 merous memory pictures usually associated with that face. Not 

 long ago I asked a man who had one of these forms of defective 

 association what his occupation was. He replied : " What I do ? 

 My business ? I know just as well as I know all of it, but I can't 

 tell," The idea of his occupation was unable to carry him on to 

 its name. He was a printer. He assured me that he could call 

 to mind his office with its presses and frames, but he could not 

 name his occupation ; yet he recognized the word printer at once 

 when I spoke it, and knew it was what he wanted to say. One 

 process of association, at least, in his brain was suspended. 



Some of the extraordinary disturbances of consciousness in 

 which an individual's personality appears to be divided, instances 

 of whicli I shall give later, seem to be explicable only on the 

 theory of the cessation of activity of the association fibers of the 

 entire brain for a time. 



I may mention here an unexpected association, a sort of spon- 

 taneous association between unrelated perceptions, which is ob- 

 served in some minds. You may have heard that there is such a 

 thing as color-hearing i. e., persons subject to this forced associa- 

 tion find that certain colors awaken forcibly the memory of cer- 

 tain sounds, which memory may be so vivid as to be a hallucina- 



