(493) 
juuft needs coagulate by the way and afterwards caufe fome 
mortal palpilationi they forclee an accident which never hap* 
ned to us, and againft which Idefireno other fecurity than 
the experience we have had of all the animals hitherto em- 
ploy'd by us, which are ftill living. 
Others who have either been witneffes of fome of ouc 
TranstufionSjOr have underftood the fame from credible re- 
lators, difpute not the poffibility of the thing f but yet not to 
authorize appears new, they (ay , That whatfoever care and 
caution be ul'd in the Transfufion,it can never be pra£tif*d up- 
on Man with fucceffe; and thcfe are their principal Rea- 
fbns»; 
Firft, The blood of a found, and the blood of a difcafed 
body having qualities very different, the one being pure^ the 
other impurc^a perfcdl mixture thereof cannot be effe^ed; 
they are two contraries, which will be at perpetual fewd^ the 
iffue whereof can be no other but the ruine and deftruftion of 
thefubjeft on whom the experiment is attempted; I wifh 
thofe that difcourfe thus , firft underftood but what they en- 
deavour to pcrfwadc others of * and that they would explaine 
to us what artifice they fancy in the Veins and Arteries^ to 
give paffage to one fort of blood & exclude another at the 
famevtime. For my ^art I confelTe I cannot comprehend 
why the continual circulation and rarefaftion made in the 
heart by the heat of its Ventricles^ are not more than (ufBcient 
to make a perfect: mixture there of thele two forts of bloodjSc 
the difficulty fecms the greater in regard experience appears to 
flatterme into a contrary opinion. For having a. few dayes 
agoe fyring'd about a quarter of a pinte of Milk into the veins 
of an Animal, andhavingopened the fame fome time after» 
we found the Milk fo perfectly mixt with the whole lubftance 
of the blood, that there was not any place wherein appear d 
the Icaft footftep of the whitenefsof Miik, and all the Blood 
was generally more liquid and lefs apt to coagulate. 
Thefecond Objedion of the fame Author is. That (hould 
the pure Blood mingle with the impure^ yet it would not 
long 
