FEVERS. 577 



interrupted in fevers. At first this appears only in what is call- 

 ed a confusion of the head, that is, we do not easily follow our 

 ordinary train of thought, which is constantly liable to be brok- 

 en off by something different and foreign to what we were em- 

 ployed about ; this difficulty and uneasiness of thought not only 

 appears by the interruption of our ideas, but we cannot easily 

 command the train we are intent upon, the memory fails us, 

 and we find the greatest difficulty in recollecting what we were 

 about. These are among the first symptoms of the disturbance 

 coming on in our intellectual faculties. Another circumstance 

 attending it, is this, that whatever slumbers are obtained are 

 disturbed by constant dreaming. I call dreaming the delirium 

 of our sleep, as delirium is the dreaming of our waking hours; 

 they are both very analogous, and turbulent and confused 

 dreams are commonly the prelude to the coming on of delirium. 

 Now commonly delirium first comes on before we are fairly 

 asleep, or when in coming out of sleep we are long in being 

 quite awake ; and this is the common account I get when I 

 inquire whether patients have been affected with any delirium, 

 that they talk a little incoherently only in coming out of sleep, 

 or in falling into it. But when a patient speaks incoherently 

 when he is evidently awake, then it is what we properly call 

 delirium. In speaking of the causes of delirium (Physiology r , 

 p. 148, First Lines, XLV.), I have mentioned that it may be 

 of two kinds, ferox or mite ; but it is the last only that I con- 

 sider here as an expression of debility, and therefore the deli- 

 rium we are to speak of now is not phrenitic ; it is without any 

 emotion or passion of the mind, without any thing like irasci- 

 bility ; it is placid and expressed by incoherent talk only ; the 

 patient has not his body agitated, and there is not any great 

 degree of restlessness, and only a degree of low muttering in- 

 coherence, with a considerable degree of sleeping at first per- 

 haps ; this however is more remarkable when it comes to be 

 accompanied with a very considerable degree of loss of memory. 

 Delirium may be owing to certain powers operating upon the 

 sensorium, and exciting false ideas that have no external object 

 corresponding to them. But these would be often banished and 

 driven away, if the memory were not lost and unable to recover 

 the ordinary association of ideas which should be most powerful 



