642 POPULAR SCIENCE MONTHLY. 



however, is still narrower, and is limited to mental states spring- 

 ing directly or indirectly from physical stimuli, especially from 

 words. 



The effects of mental states, to which I called attention in my 

 second article, were long ignored in psychology. The first to 

 obtain clear recognition was the property of producing ideas, and 

 this has become famous as " the law of association." The motor 

 effects of mental states have been more recently noted, and the 

 study of such effects is now rapidly becoming the fashion in cur- 

 rent psychology, much as the study of association came into vogue 

 in England a century ago or thereabouts. Now, the study of 

 association has been prosecuted for the most part by the psycholo- 

 gist's watching the fl.ow of his own ideas, but the effects of men- 

 tal states upon movements what Prof. Baldwin calls dyna- 

 mogeny has hitherto been studied chiefly by noting the motor 

 effects of ideas and sensations suggested from without by words 

 or physical stimuli of other kinds. Hence the word " sugges- 

 tion " has come to include among its connotations not only the 

 notion of the cause but also that of the effect especially the mo- 

 tor effect of the suggested state, and in the derivative " suggesti- 

 bility " the original meaning is almost lost ; it does not mean " a 

 condition in which mental states may be more readily initiated 

 by suitable causes," but, "a condition in which mental states, 

 however initiated, tend to work out their proper results more 

 readily than usual." From this usage, which is nowadays the 

 most common, is derived a still broader one which I shall not 

 scruple to employ. By an individual's suggestibility we denote 

 the fact that in him every mental state tends to work out definite 

 results of its own. In this sense we are all suggestible. The 

 word corresponds to dynamogeny, save that the latter term has 

 reference to the motor tendencies only of the state, while sug- 

 gestibility includes its tendency to development, its associative 

 and metabolic tendencies as well. The condition commonly 

 known as suggestibility, in which the results of the individual 

 state are more easily traced than usual, I would strictly term 

 " heightened suggestibility," but for the sake of brevity it may be 

 allowable to call it also simply suggestibility ; the context will 

 usually show what degree of suggestibility we are talking of. 



Suggestions may be subdivided with reference to their origin 

 into suggestions from without, due to impressions received 

 through the senses, and suggestions from within, arising from 

 some pre-existing thought. These are usually termed auto-sug- 

 gestions and hetero-suggestions. Both words are barbarous 

 hybrids, but the former at least is too deeply fixed in usage to be 

 displaced. The distinction is sometimes of importance, since 

 many patients who are very suggestible from within are not at 



