X SUBJECTIVE SENSATIONS 441 



and the prickling of the skin, which may sometimes be 

 due to certain states of the cii'culation, but probably more 

 frequently to processes going on in the central nervous 

 system. The subjective evil smells and bad tastes which 

 accompany some diseases are, in a similar way, very 

 probably due to disturbances in the brain in the central 

 end-organs of the nerves of smell and taste. 



Many persons are liable to what may be called anditory 

 spectra — music of various degrees of complexity sounding 

 in their ears, without any external cause, while they are 

 wide awake. I know not if other persons are similarly 

 troubled, but in reading books written by persons with 

 whom I am acquainted, I am sometimes tormented by 

 hearing the words pronounced in the exact way in which 

 these persons would utter them, any trick or peculiarity 

 of voice, or gesture, being, also, very accurately repro- 

 duced. And I suppose that everyone must have been 

 startled, at times, by the extreme distinctness with 

 which his thoughts have embodied themselves in apparent 

 voices. 



The most wonderful exemplifications of subjective sen- 

 sation, however, are aflForded by the organ of sight. 



Any one who has witnessed the suiferings of a man 

 labouring under delirium tremens (a disease produced by 

 excessive drinking), from the marvellous distinctness of 

 his visions, which sometimes take the forms of devils, 

 sometimes of creeping animals, but almost always of 

 something fearful or loathsome, will not doubt the inten- 

 sity of subjective sensations in the domain of vision. 



But in order that illusive visions of great distinctness 

 should appear, it is not necessary for the nervous system 

 to be thus obviously deranged. People in the full 

 possession of their faculties, and of high intelligence, may 

 be subject to such appearances, for which no distinct 

 cause can be assigned. An excellent illustration of this 

 is the famous case of ]\Irs. A. given by Sir David Brewster, 

 in his Xatuial Magic. This lady was subject to un- 



