310 CORRESPONDENCE OF RAY. 



than by its pressure and elasticity in keeping and crowd- 

 ing together into a vertex the igneous particles, as I have 

 hinted in the treatise ' De Antris Lethiferis.' For I can- 

 not conceive how the air that comes to the mouth of an 

 oven can serve for a pabulum to the flame which is in the 

 bottom of the oven, for it cannot come near it ; so that I 

 am apt to believe that the candle goes out in the air-pump, 

 only because, the air being exhausted, there remains 

 nothing to keep together the flying parts of the candle, 

 and so they soon vanish away ; not because there wants a 

 pabulum of air or nitre, since the sulphureous parts of the 

 candle itself are pabulum enough. 



From these and several other reasons I have concluded 

 that the intestine motion of the blood is a true fermenta- 

 tion arising from the struggling of its saline parts, and 

 mitigated by its sulphureous ones, like the fermentation of 

 beer, wine, or cider, though in a higher degree. This 

 fermentation causes heat in the blood, this heat expands 

 and rarefies the air that comes in by respiration : the 

 expanded air expands reciprocally the blood, and makes 

 it frothy, thin and florid. So that respiration is indis- 

 pensably necessary for life, to be a constant cause of the 

 attenuation and subtilization of the blood ; though the 

 sulphur of the blood is not supposed by me to be the 

 cause of this heat, yet it is very necessary to bridle and to 

 keep together the saline principles, and to hinder them 

 from evaporating too soon till new ones are supplied by 

 the chyle ; so by its pliable and limber oblong particles it 

 wraps up and keeps close together the volatile principles 

 of the blood, that otherwise might fly away. This is, sir, 

 in few words, what I think of this subject, which I submit 

 entirely to your better judgment, contending for nothing 

 else but truth. 



