732 Dynamic Theory. 



ulus does. The same is true of those actions the stimulus for which is 

 derived from the vegetative organism of the body. An animal which 

 is prompted to eat only by a sense of " goneness " in the stomach, will 

 stop as soon as the sensation changes to one of fullness. But if his 

 motive to eat is the pleasant taste of the food, he may continue to stuff 

 to the point of uncomfortable and injurious distension; that is, until 

 the pleasure of the gratification of taste is counterbalanced by the pain 

 of plethora. The motive to eat for the gratification of taste, comes 

 from the cerebrum, and consists of the suggestion of pleasurable sensa- 

 tion arising from the memory cells of that sense in the cerebrum. It 

 is the same with all the other sensual gratifications, their stimulations 

 arising from the ideas originating in the cerebral memories. We thus 

 distinguish these from the vegetative appetites which arise from states 

 of the stomach, and other viscera, and the conditions of glandular se- 

 cretions. Thus, sexuality with the lower animals is a vegetative appe- 

 tite, and recurs periodically under control of the seasons, while with 

 men and apes it is largely a cerebral appetite founded upon ideas and 

 memories, and not limited by periodical states. It is obvious how ap- 

 petites and sentiments, which depend chiefly upon ideas, may be devel- 

 oped without limit. And when abnormally developed, they may be- 

 come abnormally influential in ruling the conduct. 



An idea which has become extravagantly intensified, necessarily leads 

 to distorted views upon everything which is founded directly or remotely 

 upon it. It becomes a hobby or a mania, according to its force, and 

 warps or overpowers other ideas in the formation of the will. Thus, 

 when witchcraft was a prevalent idea, it became natural to attribute any 

 strange misfortune or malady to the evil influence of witches. Such 

 ideas may become epidemic, and fantastically influence the lives and 

 characters of nations of people. The universal belief in miracles, de- 

 mons, &c. , during the middle ages, had such distorting effect. Indi- 

 vidual cases of the abnormal growth of ideas to an extravagant degree, 

 are not uncommon, and they often become instigators of immoral or 

 criminal impulses. 



An example of impulsive insanity is given of a woman in an Edin- 

 burgh lunatic asylum, in 1850. ( Carpenter.) She was possessed of an 

 intense desire to strangle somebody, it did not make any difference 

 whom. She tried it on a number of persons, including her own nieces. 

 In other respects her ideas were sane enough, and she was perfectly 

 aware of the insanity and criminality of her impulse. The tendency 

 to the disease was hereditary. Her mother and sister both committed 

 suicide. 



There is no doubt that in eveiy community there tire numbers of per 

 sons some of whose emotional ideas are in a state of chronic exultation 



