From Robert Burton's Anatomy of Melancholy, 1621 (etc.), Part I, Sect. 2 (Mem.3, Subsect. xv):
SUBSECT. XV. —Love of Learning, or overmuch Study. With a Digression on the Misery of Scholars, and why the Muses are Melancholy.
Leonartus Fuchsius, Instit. lib. 3, sect. I, cap. I; Felix Plater, lib. 3 de mentis alienat.; Herc. de Saxonia, tract. post. de melanch. cap. 3, speak of a peculiar fury which comes by overmuch study (8). Ferlenius, lib. I, cap. 18, puts study, contemplation, and continual meditation as an especial cause of madness (9): and in his 86th consul. cites the same words. Jo. Arculanus, in lib. 9 Rhasis ad Almansorem, cap. 16, amongst other causes reckons up studium vehemens [passionate study]: so doth Levinus Lemnius, lib. de occul. nat. mirac. lib. I, cap. 16.
(8) Peculiaris furor, qui ex literis fit.
(9) Nihil magis auget, ac assidua studia, et profundae cogitationes.
"Many men" (saith he) "come to this malady by continual study (1), and night-waking, and of all other men, scholars are most subject to it" (2); and such, Rhasis adds, "that have commonly the finest wits" ()3) (Cont. lib. I., tract. 9). Marsilius Ficinus, de sanit. tuenda, lib. I, cap. 7, puts melancholy amongst one of those principal plagues of students, 'tis a common moll unto them all, and almost in some measure an inseparable companion. Varro belike for that cause calls tristes philosophos et severos [philosophers sad and austere]; severe, sad, dry, tetric, are common epithets to scholars: and Patricius thereefore (4), in the institution of princes, would not have them to be great students. For (as Machiavel holds) study weakens their bodies
