124 TH 3 INTELLECTUAL RISE IN ELECTRICITY. 



tion and its needs. 1 This was practically giving to the 

 nature-soul of the ancient Greeks a selective capacity. 

 In the 9th and loth centuries the Arabs applied the same 

 doctrine to the magnet. Serapion says that a solvent 

 medicine, when it reaches the stomach, then draws with 

 an attractive virtue the humor suitable to itself, but it is 

 not drawn to the humor; just as the magnet moves the 

 iron to itself, but is not moved to the iron. 2 AH ben 

 Abbas likewise makes a similar comparison, 3 which, in 

 later writers, is repeated over and over again, although it 

 is essentially false, and simply due to the iron being more 

 weakly magnetized than the attracting lodestone. 



The doctrine of similitudes is thus a mediaeval form of 

 the old canon similia similibus, and rests on the same 

 concepts. All compounds, for example, were supposed to 

 derive their qualities from their elements by resemblance, 

 being hot by reason of a hot element, heavy in virtue of a 

 heavy element, and so on. For a long period, medical 

 science rested on these distinctions, disorders being hot 

 and cold, and remedies being similarly classified. One 

 Eastern story teller relates 4 that the Persian physicians were 

 scandalized by the prescription of mercury by a European 

 brother, for the cure of ill-effects following over-indulgence 

 in cucumbers; for, they maintained, cucumbers are cold, 

 and hence their ill-effects can not be overcome by mer- 

 cury, which is cold also. "He makes no distinction," 

 complain the oriental practitioners, "between hot and 

 cold diseases and hot and cold remedies, as Galeuus and 

 Avicenna have ordered, but gives mercury as a cooling 

 medicine." 



1 Martin : Obs'ns and Theories of the Ancients on Magnetic Attractions 

 and Repulsions. See also Atti dell' Accademia Pont, de Nuovi Liucei, 

 T. xviii., 1864-5. 



2 Steinschneider : Intorno ad alcuni passi di Opere del Medio Evo rela- 

 tivi alia calamita. Rome, 1868. 



8 Lib. Practicae, lib. ii. c., 53. 



*The Adventures of Hadji Baba. Ed. by J. Morier, N. Y., 1855, p. 98. 



