( 106 ) 



row and the ncrvt^s ; and tliat, iipon the animal's death, and the 

 motion of the fluids in tlie vcflels ccafing, and the parts growing 

 cold, they collected or coagulated into irregular globules of different 

 fizes, in like manner as we fee that two or three globules of blood, 

 lying fo near as to touch each otlier, do, upon the approach of cold, 

 concrete togetlier and form an irregular figure. And as often as I 

 revolve in my mind the fituation and figure of the medullary fub- 

 ftance of the Brain, it feems to be defigned by Nature to convey the 

 blood, which in thefe innumerable fmallefl vellels, palling through 

 the vitreous part of the Brain (called the corticle), is prepared and 

 elaborated, to the fpinal marrow : fo that moft of the minute arte- 

 ries which are found in the Brain, feem made only to convey the 

 blood to the Brain, without its being returned from thence into 

 the veins ; and for this intent only, namely, that the Brain may 

 be continually fupplicd with a frefli addition of blood, and may 

 provide a conllant frelli fupply of fubflance, for the fupport and 

 iiourifliment of the fpinal marrow and the nerves. And as to the 

 objeclion which fome may make, that if the blood did really pals 

 tlirough the Brain, it would tinge the medullary fubflance of a 

 Ted colour ; fiich objedlion will be found of no force, if we con- 

 fider that a * globule of blood, fingly taken, exhibits very little of a 

 red appearance ; and, therefore, when divided into its moll minute 

 component particles, it may appear wholly colourlefs. 



Addition, by the Thanslator. 



The Tranflator begs leave to fubjoin a (ew -words to this Bflay, for the 

 information of fuch of his readers as are not converfant In the doftrine of 

 folids ; and the rather, as what the author dates refpefting the minutenefs 

 of the vefTels in the retina of the human eye may appear, at firft fight, 

 utterly incredible. But it muft be remembered, that it is the folid contents 

 of two fpheres or globes of the fizes mentioned by the author^ and not 

 ^leir refpe£live diameters, that are the u^eafure of his computation. 



* See this explained in Vol. I. page 94. 



