_Of discussive Medicines._
The nature of discussing (or sweating) medicines is almost the same
with attractive, for there are no discussive medicines but are
attractive, nor scarce any attractive medicine but is in some measure
or other discussing. The difference then is only this; that discussive
medicines are hotter than attractive, and therefore nothing else need
be written of their nature.
_Use._ Their use may be known even from their very name; for diseases
that come by repletion or fulness, are cured by evacuation or emptying;
yet neither blood nor gross humours are to be expelled by sweating,
or insensible transpiration (as they call it) but the one requires
blood-letting, the other purgation, but _scrosus_ or thin humours and
filthy vapours, and such like superfluities, are to be expelled by
sweat, and be wary in this too, for many of them work violently, and
violent medicines are not rashly to be given.
_Caution 2._ Besides, swellings are sometimes made so hard by sweating
medicines, that afterwards they can never be cured; for what is thin
being by such medicines taken away, nothing but what is perfectly hard
remains: If you fear such a thing, mix emolients with them.
_Caut. 3._ Again, sometimes by using discussives, the humours offending
(which physicians usually call the _peccant humours_) is driven to some
more noble part of the body, or else it draws more than it discusseth;
in such cases, concoct and attenuate the matter offending before you go
about to discuss it.
From hence may easily be gathered at what time of the disease
discussive medicines are to be used, viz. about the declining of the
disease, although in diseases arising from heat of blood, we sometimes
use them in the encrease and state of them.
They are known by the same marks and tokens attenuating medicines are,
viz. by their burning and biting quality, they being very hot, and of
thin parts, void of any biting quality, therefore they contract not the
tongue in tasting of them.