464 Edward Livingston Youmans. 



ever, from any cause, this activity declines, so as to sink 

 below par, a precisely opposite state of consciousness 

 arises, and the patient may fall into a profound melancholy 

 and be insanely hopeless, distrustful, and anxious as to all 

 events, past, present, and to come."* Even the variation 

 in the quantity of blood which enters the brain, by simply 

 taking the recumbent position, may affect mental activity 

 in a marked degree. Persons who, through overexertion 

 of mind, have impaired the contractility of the cerebral 

 vessels, often become intensely wakeful after lying down, 

 although very drowsy before, and sometimes can only sleep 

 in the erect position. Dendy mentions the case of an 

 individual who, when he retired to rest, was constantly 

 haunted by a spectre, which attempted to take his life ; 

 though when he raised himself in bed the phantom van- 

 ished. 



Persons have had their entire character changed by an 

 apparently trifling interference with the circulation of 

 blood in the head. "A person of my acquaintance," says 

 Dr. Hammond, " was naturally of good disposition, amiable 

 and considerate, but after an attack of vertigo, attended 

 with unconsciousness of but a few minutes' duration, his 

 whole mental organization was changed ; he became de- 

 ceitful, morose, and overbearing." Tuke and Bucknill 

 mention the instance of a conscientious lady, who recovered 

 from the brain congestion accompanying smallpox with 

 her disposition greatly changed. The susceptibility of 

 conscience had increased to a state of actual disease, dis- 

 turbing her happiness, and disqualifying her for the duties 

 of life. 



A blow on the head may produce marked mental de- 

 rangement. The memory may be dislocated, events oblit- 

 erated, and whole passages from the past life expunged: 



* Correlations of Consciousness and Organization, vol. ii, p. 325. 



