THE NERVOUS SYSTEM. 
177 
the “ feelers” (tentacles, horns, and antennae) ; 89 in the Oys¬ 
ter, the edge of the mantle is most sensitive; in Fishes, the 
lips; in Snakes, the tongue; 
in Birds, the beak and under 
side of the toes ; in Quadru¬ 
peds, the lips and tongue; 
and in Monkeys and Man, 
the lips and the tips of the 
tongue and fingers. In the 
most sensitive parts of Birds 
and Mammals, the true skin 
is raised up into multitudes 
of minute elevations, called 
papilla% containing loops of capillaries and nerve-filaments. 
At the ends of the latter are the essential organs of touch, 
the tactile corpuscles and the touch-cells. There is a corre¬ 
spondence between the delicacy of touch and the develop¬ 
ment of intelligence. The Cat and Dog are more sagacious 
than hoofed animals. The Elephant and Parrot are remark¬ 
ably intelligent, and are as celebrated for their tactual power. 
Taste is more refined than touch, since it gives a knowl¬ 
edge of properties which cannot be felt. It is always 
placed at the entrance to the digestive canal, as its chief 
purpose is to guide animals in their choice of food. Special 
organs of taste have been detected in 
only afewof the In vertebrates, though 
all seem to exercise a facility in se¬ 
lecting their food. Even in Fishes, 
Amphibians, Reptiles, and Birds this 
Fig. 148.—Papillae of Human . „ . . , 
Palm, x 35 , the cuticle be- sense is very obtuse, tor they bolt 
mg removed. their food. But the higher Verte¬ 
brates have it well developed. It is confined to the tongue, 
and is most delicate at the root. 90 A state of solution and 
an actual contact of the fluid are necessary conditions. 
Smell is the perception of odors, i. e., certain substances 
12 
Fig. 147.—Antenuae of Various Insects. 
