29^ PHILOSOPHICAL TRANSACTIONS. [aNNO 1668. 



The author in the former of these tracts having first given an account, how 

 the air by its elastic force is inspired, and upon the dilatation of the chest caused 

 by the intercostal muscles drawn upwards, rushes into the lungs, which are 

 thereby expanded, being nothing else but a body made up of very thin little 

 membranes, in the form of innumerable small bladders; delivers his thoughts 

 of the use of respiration, waving those opinions that would have respiration 

 serve either to cool the heart, or to make the blood pass through the lungs out 

 of the right ventricle of the heart into the left, or to reduce the thicker venal 

 blood into thinner and finer parts; and affirming, that there is something in the 

 air absolutely necessary to life, which is conveyed into the blood; which, 

 whatever it be, being exhausted, the rest of the air is made useless and no more 

 fit for respiration. Where yet he doth not exclude this use, that, together 

 with the expelled air, the vapours also steaming out of the blood are thrown 

 •out. 



And inquiring, what that may be in the air so necessary to life, he conjectures 

 that it is the more subtle and nitrous particles with which the air abounds that 

 are communicated to the blood through the lungs ; and this aerial nitre he 

 makes so necessary to all life, that even plants themselves do not grow in earth 

 deprived thereof, which yet, being exposed to the air, and afresh impregnated 

 by that fertilizing salt, becomes fit again to nourish those plants. 



And considering further, what part this nitrous air acts, and what operation 

 it performs in the animal life, he is of opinion, that this nitre, mixed with the 

 sulphureous parts of the blood, causes a due fermentation, which he will have 

 raised, not only in the heart alone, but immediately in the pulmonary vessels, 

 and afterwards in the arteries no less than in the heart. Examining also the 

 reason why death so suddenly ensues upon respiration suppressed, the blood 

 being then not yet unfit for motion, he inquires yet after another use of re- 

 spiration, which makes it so very necessary to life. And considering with him- 

 self that the life of animals consists in the distribution of the animal spirits, for 

 the supply of which is required the pulsation of the heart, and the afiiux of the 

 blood to the brain, it seems to him that respiration is highly necessary to the 

 motion of the heart, forasmuch as the heart is one of the muscles, the motion 

 of every one of which absolutely requires this aerial nitre, so that without the 

 same, even the beating of the heart cannot be performed. 



But here he declares that he does not see how that explosion, by which the 



physiciaimow living, we deem it unnecessary to insert in this place a biographical notice of this dis- 

 tinguished chemist and physiologist. We shall only remark, that in his writings are to be found the 

 "primordia of some of the most important theories and experiments of modern chemical philo- 

 sophers. 



