102 Mayow 



as nitro-aerial particles when they slowly enter the 

 pores of the earth encounter there saline-sulphureous 

 particles, immature indeed, in an obscure fermentation 

 on which, as has been shown elsewhere, the life of 

 plants depends ; so the same nitro-aerial particles 

 when introduced more profusely into the mass of the 

 blood b}^ the action of the lungs, and mixed in their 

 minutest parts with its saline-sulphureous particles,, 

 brought to a state of active vigour, produce a very 

 marked fermentation such as is requisite for animal 

 life. For it is to be noted that blood consists of 

 the same. particles as earth but in a more exalted state. 

 For as immature sulphur, when closely combined with 

 the seeds of a fixed salt, composes earthy matter, as has^ 

 been said elsewhere, ^o the mass of the blood is 

 made up of saline-sulphureous particles raised to a 

 suitable volatility, and hence it is that both have 

 the same colour — to wit, a dark purple. Indeed I 

 attempted to show above that nearly all fermentations 

 of natural things result from the motion of nitro-aerial 

 particles ; and in fact I have no doubt at all that the 

 effervescence of the blood is due to the same cause : 

 accordingly when respiration is arrested, the effer- 

 vescence of the blood immediately ceases and animal 

 life is extinguished. 



And what confirms still more the view just stated is. 

 the fact that the blood which entered the lungs with, 

 a dark colour, returns from them m.ore florid and 

 ruddy, as arterial blood is, as was observed by the: 

 illustrious Lower in vivisections. He also showed 

 that that change made in the mass of the blood is 

 caused, not so much by its being triturated in the 

 lungs as by the air being mixed with it. For when 

 venous blood is placed in a vessel, the upper surface 

 which is exposed to the air acquires a scarlet and 



