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Webster 1913 Edition
Irritability
Irˊri-ta-bil′i-ty
,Noun.
[L.
irritabilitas
: cf. F. irritabilité
.] 1.
The state or quality of being irritable; quick excitability; petulance; fretfulness;
as,
. irritability
of temper2.
(Physiol.)
A natural susceptibility, characteristic of all living organisms, tissues, and cells, to the influence of certain stimuli, response being manifested in a variety of ways, – as that quality in plants by which they exhibit motion under suitable stimulation; esp., the property which living muscle possesses, of responding either to a direct stimulus of its substance, or to the stimulating influence of its nerve fibers, the response being indicated by a change of form, or contraction; contractility.
3.
(Med.)
A condition of morbid excitability of an organ or part of the body; undue susceptibility to the influence of stimuli. See , 3.
Irritation
, Noun.
Webster 1828 Edition
Irritability
IRRITABIL'ITY
,Noun.
1.
In physiology, one of the four faculties of the sensorium, by which fibrous contractions are caused in consequence of the irritations excited by external bodies. Irritability differs from sensibility; the most irritable parts of the body not being at all sensible, and vice versa. The heart is endued with the greatest irritability.