416 NATURAL HISTORY. 



than wounds made with iron. The cause is, for hat 

 brass hath in itself a sanative virtue ; and so in the 

 very instant helpeth somewhat : but iron is corrosive 

 and not sanative. And therefore it were good, that 

 the instruments which are used by chirurgeons about 

 wounds, were rather of brass than iron. 



Experiment solitary touching mortification by cold. 



788. In the cold countries, when men s noses and 

 ears are mortified, and, as it were, gangrened with 

 cold, if they come to a fire they rot off presently. The 

 cause is, for that the few spirits that remain in those 

 parts, are suddenly drawn forth, and so putrefaction 

 is made complete. But snow put upon them helpeth : 

 for that it preserveth those spirits that remain, till 

 they can revive ; and besides, snow hath in it a 

 secret warmth : as the monk proved out of the text ; 

 &quot; qui dat nivern sicut lanam, gelu sicut cineres 

 spargit.&quot; Whereby he did infer, that snow did warm 

 like wool, and frost did fret like ashes. Warm 

 water also doth good ; because by little and little it 

 openeth the pores, without any sudden working upon 

 the spirits. This experiment may be transferred to 

 the cure of gangrenes, either coming of themselves, 

 or induced by too much applying of opiates ; wherein 

 you must beware of dry heat, and resort to things 

 that are refrigerant, with an inward warmth, and 

 virtue of cherishing. 



Experiment solitary touching weight. 

 789. Weigh iron and aqua fortis severally ; then 



