io6 Mayow 



off is soon coagulated and acquires a certain consist- 

 ence. But such things as are possessed of consistence, 

 even in the opinion of this learned man, generate heat 

 in effervescing. Further, blood abounds beyond all 

 other liquids in saline-sulphureous particles, and nitro- 

 aerial spirits are densely and most minutely mixed 

 with them, and when these effervesce together, as it is 

 their nature to do, an intense enough heat must arise ; 

 while in other liquids, fermentation is only produced 

 by a much more minute quantity of nitro-aerial and 

 saline-sulphureous particles. Further, the nitro-aerial 

 spirit by which fermentation is excited in other liquids 

 is not supplied directly from the air with motion 

 and vigour but is innate in these liquids themselves, 

 wrapt in the embrace of the salt and fixed, as has been 

 shown elsewhere. 



But yet another difficulty brought forward by this 

 eminent man opposes what has been said — viz., that the 

 action and heat of contrary salts effewescing together 

 ai'e increased in a vactmni^ as is proved by Boyle's 

 experiments. Wherefore^ if the heat of the blood were 

 caused by its fermentation^ it ivould seem that it ought 

 to become more intense when the air is withdrawn. But 

 on the contrary^ if by suppressing respiration air is pre- 

 vented from entering the bloody fermentation soon ceases 

 and the animal quickly dies. 



I reply that from the fact that the fermentation of 

 the blood immediately ceases on account of want of 

 air, it follows that it is caused by nitro-aerial spirit, as- 

 has just been said. 



Further, although contrary salts when mixed to- 

 gether, and other things of a like kind when ferment- 

 ing, expand and rise more in a place void of air than 

 elsewhere, still it is by no means on that account to 

 be granted that they effervesce more intensely. For 



