On Popular IlluJ/ons. 83 



to the other theories already mentioned. But if it 

 be allowed, that the imagination of another can 

 produce fo wonderful an impreffion on the mind, 

 how much more eafy is it to conceive a man's 

 own imagination impofing delufions on him ? 

 There are many moments, when the opera- 

 tions of fancy are extremely fallacious in heal- 

 thy men ; and in nervous difeafes, where the 

 patient appears but little altered in the ftrength 

 of his faculties, there is much tranfient delirium, 

 and much falfe imagination. When the fancy 

 is once fet in motion, old imprefiions generally 

 revive, and friends and relations rulh upon us j 

 the caprices of aflTociatio.n in fome perfons are 

 unaccountable; and many may cry out with the 

 poet*, delirando to vivo. 



One cannot help regretting, that fo much 

 ingenuity and attention had not rather been 

 applied to an accurate examination of fadls, 

 than to form theories, which only fliew how 

 irreconcileable thofe fafts are with reafon and 

 experience ; but it has generally been found, 

 that an opinion, adopted without fufficient proof, 

 is defended with an earneftnefs very unfriendly 

 to inveftigation ; and we are going to fee fuch 

 aftonifhing perverfion of fa6ls, and fuch obfti- 

 nate adherence to the moft extravagant abfur- 

 dities, that what has hitherto been related will 



* Metaftafio. 

 G 2 ' appear. 



