good health, and are perhaps sufficiently marked to be
distinguished from each other, and constitute the temperaments or
predispositions to the irritative, sensitive, voluntary, and associate
classes of diseases.

I. _The Temperament of decreased Irritability._

The diseases, which are caused by irritation, most frequently originate
from the defect of it; for those, which are immediately owing to the excess
of it, as the hot fits of fever, are generally occasioned by an
accumulation of sensorial power in consequence of a previous defect of
irritation, as in the preceding cold fits of fever. Whereas the diseases,
which are caused by sensation and volition, most frequently originate from
the excess of those sensorial powers, as will be explained below.

The temperament of decreased irritability appears from the following
circumstances, which shew that the muscular fibres or organs of sense are
liable to become torpid or quiescent from less defect of stimulation than
is productive of torpor or quiescence in other constitutions.

1. The first is the weak pulse, which in some constitutions is at the same
time quick. 2. The next most marked criterion of this temperament is the
largeness of the aperture of the iris, or pupil of the eye, which has been
reckoned by some a beautiful feature in the female countenance, as an
indication of delicacy, but to an experienced observer it is an indication
of debility, and is therefore a defect, not an excellence. The third most
marked circumstance in this constitution is, that the extremities, as the
hands and feet, or nose and ears, are liable to become cold and pale in
situations in respect to warmth, where those of greater strength are not
affected. Those of this temperament are subject to hysteric affections,
nervous fevers, hydrocephalus, scrophula, and consumption, and to all other
diseases of debility.

Those, who possess this kind of constitution, are popularly supposed to be
more irritable than is natural, but are in reality less so.

This mistake has arisen from their generally having a greater quickness of
pulse, as explained in Sect. XII. 1. 4. XII. 3. 3.; but this frequency of
pulse is not necessary to the temperament, like the debility of it.

Persons of this temperament are frequently found amongst the softer sex,
and amongst narrow-shouldered men; who are said to bear labour worse, and
pain better than others. This last circumstance is supposed to have
prevented the