CHAP. XXXIV. Of the causes of the stone.
THE stones which are in the bladder have for the most part had their first originall in the reines or kidneys, to wit, falling down from thence * 1.1 by the ureters into the bladder. The cause of these is twofold, that is, materiall and efficient. Grosse, tough, and viscide humours, which crudities produce by the distempers of the bowels and immoderate exercises, chiefly immediately after meat, yeeld matter for the stone; whence it is that chil∣dren are more subject to this disease than those of other ages. But the efficient cause is either the immoderate heate of the kidneys, by meanes whereof the subtler part * 1.2 of the humors is resolved, but the grosser and more earthy subsides, and is hardened as we see bricks hardened by the sun and fire; or the more remisse heat of the blad∣der, sufficient to bake into a stone the faces or dregges of the urine gathered in great plenty in the capacity of the bladder. The straightnesse of the ureters and urenary passage may be accounted as an assistant cause. For by this meanes the thinner por∣tion of the urine floweth forth, but that which is more feculent and muddy being stayed behind, groweth as by scaile upon scaile, by addition and collection of new matter into a stony masse. And as a weeke often-times dipped by the Chandler into melted tallow, by the copious adhesion of the tallowy substance presently becomes a large candle; thus the more grosse and viscide faeces of the urine stay as it were at the barres of the gathered gravell, and by their continuall appulse are at length wrought and fashioned into a true stone.