But if early studies are hurtful, it is no less dangerous to attach oneself to study in an advanc’d age; for habit becomes gradually a second nature when we begin from our tender age; but at an advanc’d period it is no longer susceptible of new habits; and the fibres of the brain accustom’d to rest, are torn before they can receive new and regular motions. I not long since with difficulty cur’d a native of this country, who in his fortieth year laying aside mercantile business, to pore night and day over the works of NEWTON, CLARKE and LOCKE, had totally disorder’d his brain. He recovered his health by remedies, by a cessation of study, and amusing conversation; but the joy was but short-liv’d, for by again dipping into the sublime, geometry, and metaphysical abstractions, he once more lost his senses[36]. Nor is it less laborious to continue our accustom’d studies too long, when old age approaches. The soul that animates our bodies, is indeed immortal; but so long as it is connected with a feeble frame, it must be influenc’d by its nature. _Gigni pariter cum corpore, & una_ _Crescere sentimus, pariterque senescere mentem._ _Besides, ’tis plain, that souls are born and grow,_ _And all by age decay, as bodies do._ CREECHE’S Lucretius, book 3. The labours of the mind should therefore be retrench’d, as the declining powers of the body direct; the latter becomes incapable of bearing the same burthens, the former of pursuing the same studies, which in this period of life soonest break the constitution, and destroy the brain; and are of so little use, that old men consult their glory no less than their health, by retiring betimes. _Solve senescentem mature sanus equum, ne_ _Peccet ad extremum ridendus, & ilia ducat._ _Loose from the rapid car your aged horse,_ _Lest in the race, derided, left behind,_ _He drag his jaded limbs, and burst his wind._ FRANCIS’S Horace, lib. 1. ep. 1. But it grieves me, respectable auditors, that you should be obliged to hear of so many disorders, and I to give an account of them; so I shall say no more of so melancholy a subject, but proceed to treat of the remedies for the several diseases.