164 Mayow 



each other would by no means separate them from 

 each other. Nay, if such an acid existed in sulphur, 

 it would hinder altogether the union of the sulphur 

 and the alkaline salt ; since all acids (but especially 

 one so corrosive as oil of sulphur) have the power of 

 separating sulphur from fixed salt and precipitating it. 

 I further remark that acid salts do not combine with 

 alkaline salt or even with metals, without effervescence 

 and a notable degree of heat. But such is not the 

 case when sulphur combines with either of them ; so 

 that clearly the combination of sulphur with fixed salt 

 would appear to result not so much from any 

 antagonism as from their mutual affinity, as has 

 already been shown in some detail. 



I may here further^ remark, by the way, that salts 

 of different kinds should not without the greatest 

 caution be compounded together in the same medicine, 

 lest one of them should entirely destroy the efficacy of 

 another, and even change it into something quite 

 difTerent from what it was at first. For example, 

 when obstructions or a diminished fermentation of the 

 blood, point to the use of steel, it seems to me 

 inadvisable to mix the salt of wormwood or any 

 lixivial salt with the vitriol of Mars or with the 

 aperitive Crocus Martis. For when that medicine 

 dissolves in the stomach, the acid salt which the 

 vitriol of Mars contains will immediately unite with 

 the lixivial salt, and meanwhile the metaUic part of the 

 vitriol, driven out from its acid fellowship of the salt, 

 will be precipitated as Colcothar or astringent Crocus 

 Martis^ which is by no means aperitive. For the case 

 will be very much as if the acid salt of the said vitriol 

 were expelled by fire, when nothing metallic will be 

 left but Colcothar or astringent Crocus Martis. And 

 indeed the lixivial salt also mixed with the said vitriol. 



