He deſcribes in a Mechanical way the manner of its Action; ſuppoſing that ſome of its Particles having undergone ſeveral Comminutions (tho not a Diſſolution) from the various Firments they have paſſed, arrive at laſt, with the Blood, at the Brain; […] thoſe of them, which are not ſmall enough to paſs thoſe Straits along with the Juice, being juſt admitted, ſtick there till other appelling Subſtances give them a farther Comminution, and ſo pretrude them along: […]