648 POPULAR SCIENCE MONTHLY. 



started, they work out their proper results with almost fatal pre- 

 cision. 



Turning now from the theory underlying these phenomena to 

 the actual facts, we may say that heightened suggestibility is 

 found under three chief groups of circumstances. First, it is 

 found in sleep occasionally, and more frequently in the states 

 akin to sleep termed hypnotic. Second, it is sometimes found as 

 one of the symptoms produced by certain drugs. As we suppose 

 these symptoms to be due to poisons circulating in the blood, the 

 type is termed toxaemic suggestibility, from two Greek words 

 meaning blood poison. In the last place, heightened suggestibil- 

 ity is found as a spontaneous phenomenon for which no reason 

 can be given. This is called idiopathic suggestibility. 



Of these three forms, hypnotic suggestibility is the best known 

 and for many reasons the most interesting. Dreams, as I have 

 already pointed out (February number), are largely due to sug- 

 gestions given in sleep. A higher degree of suggestibility is 

 sometimes found in normal sleep. A friend of mine told me that, 

 when a boy, he had a schoolmate who became highly suggestible 

 whenever he was slightly disturbed in sleep. Without awaking, 

 he would become partly conscious and would do everything, no 

 matter how preposterous, which the mischievous ingenuity of the 

 boys could suggest. In hypnotic states suggestibility is so con- 

 stantly found that some propose to regard it as an essential char- 

 acteristic. Let me give a few illustrations of its varying forms. 

 T - B is a laborer, twenty-three years of age, neurotic, in- 

 temperate, easily hypnotized. His muscles are entirely at my com- 

 mand. I can stiffen a finger or an arm by a word so that he can 

 not bend it. I can even contract one set of muscles while leaving 

 the opposite set under his control. I bring his hands together, 

 place the tips of his fingers in contact, and tell him he can not sepa- 

 rate them. The systems of muscles necessary to hold them together 

 are strongly innervated, while those that pull them apart are left 

 under his control; he struggles in vain to part them, and his 

 struggles are such as could not be easily imitated voluntarily. 

 I can control his sensations in the same way. I can abolish his 

 sensations of pain, of touch, of sight, and of hearing. I tell him 

 he will feel in his right hand what I do to his left ; I then put a 

 lighted match to his left hand and it remains at rest, while the 

 right jerks violently about in its efforts to escape from the fire. 

 I tell him he is blind, and he is deaf, and he can hear nothing. 

 I tell him he can not see or hear such a man, and he acts as if he 

 were unconscious of his presence. I can create hallucinations of 

 all the senses also. 



The limitations of suggestibility are even more interesting. 

 B is a college graduate and is now a student of divinity. 



