occultam naturam curandi variolas. Similiter pannus tinctus de
grano._"

Acid and saline articles of food should be avoided, sweets used
freely, and the patients should be carefully guarded from cold.

Not the least interesting pages of the Compendium are those (there are
about twenty of them) devoted to the discussion of poisons, poisoned
wounds and hydrophobia.

An introductory chapter on the general subject of the character of
poisonous matters, illustrated by some gruesome and Munchausen-like
tales, borrowed mainly from Avicenna and Ruffus, on the wonders
of acquired immunity to poisons, the horrors of the basilisk, the
_armaria_ (_?_), the deaf adder (_aspis surda_) and the red-hot
_regulus_ of Nubia, leads naturally to the consideration of some
special poisons derived from the three kingdoms of nature. Very
characteristically Gilbert displays his caution in the discussion of a
dangerous subject by the following preface:

_Abstineamus a venesis occultis quae non sunt manifesta, ne virus in
angues adjiciamus, aut doctrinam perniciosam tradere videamur_ (f. 351
a).

Beginning then with metallic mercury (_argentum vivum_), he considers
the poisonous effects of various salts of lead and copper, the
vegetable poisons hellebore, anacardium (_anacardis?_), castoreum,
opium and cassilago (_semina hyoscyami_), and then proceeds to
the bites or rabid men and animals, hydrophobia, and the bites of
scorpions, serpents and the _animalia annulosa_, that is, worms,