236 M. Dumeril on the General Movements of Serpents. 
nearly alike, which thus afford a point of insertion to a great number of 
fascicles of moveable fibres destined to produce and repeat, each by itself, 
in a continuous and most regular manner, all the movements which are 
impressed upon them singly. This long spine, or moveable frame-work, 
is moreover perforated throughout its whole length, forming a continu- 
ous canal, which receives and protects the nervous marrow prolonged 
from the brain. Through holes, symmetrically arranged between each of 
these numerous vertebrae, issue at like intervals pairs of nerves which are 
distributed and terminated in every part of the body. 
This general structure of the organs adapted for movement, seems to 
have necessitated the most important modifications in respect to their 
forms and relative situation, in all the instruments which exercise the 
functions of general or vegetative life, such as those of nutrition and pro- 
pagation. Yet the means which serve to establish the relations between 
these animals and the external world, by the aid of the senses, are nearly 
the same as in other reptiles. 
A serpent being deprived, at least to appearance, of instruments 
adapted to divide its prey, which must be swallowed without ¢hewing, 
the victim must necessarily be pursued, stopped, laid hold of, and swal- 
lowed entire, as it were at a single mouthful. These circumstances have 
caused faculties altogether of a special nature to be attributed to serpents. 
Sometimes an extreme and sudden agility, an excessive flexibility, sup- 
pleness, and rapidity in its movements, are conferred on a serpent, in 
order that it may be able to reach the animal it covets as a prey ; at other 
times, and more frequently, exerting a prodigious constrictive power, and 
the most active muscular energy, the serpent attacks animals greatly sur- 
passing itself in size. It darts upon them, envelopes them, squeezes them 
together, and suffocates them, compressing and breaking their bones be- 
tween its tortuous folds and numerous circumvolutions, although they 
are often thicker than its own body. It can enlarge the size of its belly, 
however, at pleasure, and succeeds in getting them into it after bruising 
their flesh within the skin that covered it. 
Other species, of inferior activity and strength, are capable of fascina- 
tion, a power which has been regarded as magnetic or supernatural, pro- 
ducing in the prey on which they fix their gaze, a kind of stupor or in- 
stinetive dread, which paralyzes the animal’s movements and efforts, 
in vain desirous to withdraw and escape the fatal destiny which awaits 
it. In like manner, we see how a pointer dog can influence from a 
distance, solely by his look, the‘game he has discovered ; the latter dare 
not move for the purpose of escape, for fear of betraying its presence by 
its motion ; it then appears arrested by a magical power which suspends 
all its faculties ; it seems impossible for it to escape from a danger so 
imminent ; it gives way to the torture of despair, and if its strength fail, 
sinks and is devoured. 
Finally, some other kinds of ophidians, after having borne very long 
abstinence, and when they feel the urgent need of food, are all at once 
