148 PHYSIOLOGY. 



grees from the placid, quiet dream which is hardly recollected, 

 to one that raises considerable emotions, that awakes us to cer- 

 tain functions, and gives occasion to somnambulism. 



" We observe, accordingly, that a state of delirium generally 

 occurs between the states of sleeping and waking, one part of 

 the brain being excited while another part is under collapse. 

 Of this kind of delirium there will be two cases ; one, while in 

 sleep, the greater part of the brain being in a state of collapse, 

 stimuli are applied, which excite only one part of the brain, in 

 which intermediate state delirium will occur ; the other, where, 

 the person being awake, the powers producing sleep have acted 

 and have affected certain parts of the brain only, from which 

 cause the same unequal state of delirium must equally arise. 



" No state can be more like common delirium than those con- 

 ditions of dreaming ; and we should consider both as always of 

 the same nature, if dreaming had not become so common and 

 familiar to us. See how Haller explains dreaming (Prim. Lin. 

 578,) ; and the same views in Gaubius ( 7^2,), who also 

 says that one part of the brain may be excited while another is 

 under a collapse. 



" This accordingly is the foundation of dreaming, and there- 

 fore of delirium also, according to a general principle the want 

 of an equal communication between the several parts of the 

 brain ; and this may arise either from organic affections, or pure- 

 ly from some transitory difference in the states of excitement 

 and collapse, connected with the states of sleep and waking. 

 This opens to us a particular view ; it does not leave the whole 

 causes of delirium resting, as Gaubius has assigned, upon a 

 more considerable change in the organization of the brain ; and 

 it shows that other powers occurring in diseases may produce 

 collapse, and thereby lay the foundation of delirium. In some 

 of the most violent instances, indeed, mania can be discussed, 

 and the mind restored to its healthy state, almost as easily 

 as sleep and dreaming are discussed and the waking state re- 

 stored. Whoever has considered this subject will see its ap- 

 plication in distinguishing two cases of delirium as depending 

 upon the last mentioned causes, viz. that which arises from an 

 uncommon degree of stimulus applied to an unequal portion of 

 the brain, where the whole cannot be equally excited ; and that 



