for at those early periods of life, the sensation affects the
organ of smell, much more powerfully, than after the repeated habits of
smelling has inured it to odours of common strength: and in our adult
years, the stronger smells, though they are at the same time agreeable to
us, as of volatile spirits, continue to produce an increased secretion of
tears.

This pleasing sensation of smell is followed by the early affection of the
infant to the mother that suckles it, and hence the tender feelings of
gratitude and love, as well as of hopeless grief, are ever after joined
with the titillation of the extremity of the lacrymal ducts, and a
profusion of tears.

Nor is it singular, that the lacrymal sack should be influenced by pleasing
ideas, as the sight of agreeable food produces the same effect on the
salivary glands. Ac dum vidimus insomniis lascivae puellae simulacrum
tenditur penis.

Lambs shake or wriggle their tails, at the time when they first suck, to
get free of the hard excrement, which had been long lodged in their bowels.
Hence this becomes afterwards a mark of pleasure in them, and in dogs, and
other tailed animals. But cats gently extend and contract their paws when
they are pleased, and purr by drawing in their breath, both which resemble
their manner of sucking, and thus become their language of pleasure, for
these animals having collar-bones use their paws like hands when they suck,
which dogs and sheep do not.

4. _Of Serene Pleasure._

In the action of sucking, the lips of the infant are closed around the
nipple of its mother, till he has filled his stomach, and the pleasure
occasioned by the stimulus of this grateful food succeeds. Then the
sphincter of the mouth, fatigued by the continued action of sucking, is
relaxed; and the antagonist muscles of the face gently acting, produce the
smile of pleasure: as cannot but be seen by all who are conversant with
children.

Hence this smile during our lives is associated with gentle pleasure; it is
visible in kittens, and puppies, when they are played with, and tickled;
but more particularly marks the human features. For in children this
expression of pleasure is much encouraged, by their imitation of their
parents, or friends; who generally address them with a smiling countenance:
and hence some nations are more remarkable for the gaiety, and others for
the gravity of their looks.

5. _Of Anger._

The actions that constitute the mode of fighting, a