294 PHILOSOPHY OF ZOOLOGY. 
to those to whom they are addressed, although, in the case 
of insects, the organs which receive the impression have 
hitherto eluded the researches of the anatomist. 
b. On the mutual communication of Feeling, by means. 
of Signs addressed to the Eye.—In attending to such signs, 
it is convenient to divide them into Natural, and Artificial, 
or Acquired. 
The natural signs are common to many animals, and ex- 
hibit constant and uniform characters in the individuals of 
each species. ‘They have obtained the name of gestures, as 
they require for their expression the movement of certain 
parts of the body. 
The gestures by which man expresses his feelings, are 
executed by the face and hands. By the former, he indi- 
cates the state of his heart, in a manner perfectly intelligi- 
ble to all his race, expressing, by the position of his lips, 
and motion of his eyes and eye-brows, fear, anger, joy, grief 
or pain. Each sense has an expression peculiar to itself, 
intimating, whether the sensations which it experiences are 
pleasant or disagreeable. ‘The hands are chiefly employed 
in expressing the conditions of distance or place. These 
different signs, in man, are carefully studied by actors of 
pantomime ; and it is astonishing with what distinctness 
they are able, by a judicious use of them, to express a great 
variety of feeling and passion. 
In the lower animals, the gestures are not so much confin- 
ed to the countenance as in man. In the dog, however, we 
can read in the face, chiefly from the position and motion of 
the eye-brows, whether he is pleased or offended. The ex- 
pression of the former feeling is accompanied by a motion 
of the tail from side to side. The bull expresses his dis- 
pleasure, by bending his head to the ground, and throwing 
up earth with his forefeet and horns. 'The horse testifies 
surprise or anger by pointing his ears forwards or back. 
