239 
ON THE NINTH PAIR OF NERVES. 
many of the voluntary muscles are, with organic life, and with 
two of its main functions—digestion and respiration. 
The Function of this Nerve as connected with Digestion. —the 
spinal and cerebral motor nerves are under the influence of the 
will • but before the understanding can be said to have existence, 
or a volition (the result of some mental act) can be formed, the 
animal requires nutriment; and he is guided to it, and to the recep¬ 
tion and the disposal of it, unerringly and perfectly, the toa , 
the calf, the lamb, seek out the teat, and, with an accuiacy on 
which the experience of after-existence cannot improve, extract 
and swallow the milk. The principle of organic life is in lull 
power, and has been so long ere this ; and we shall, perhaps, by- 
and-bv, see reason to conclude, that these nerves from the lateral 
column are influenced by this principle before the will could issue 
its mandate, and likewise designed to call into requisition, and 
to controul and combine, the action of the voluntary nausc es 
when, afterwards, the purposes of organic life require it. We are 
little conscious of the varied influence of the muscles ot the 
tongue in the act of deglutition. The animal acquired the pow¬ 
er of performing this organic operation without experience, and 
without mental exertion ; and he continues to perform it, I will 
not say without an effort of the will, but in perfect unconscious¬ 
ness of the various steps of the process. 
This a Respiratory Nerve as it regards the longue. — the 
tono-ue is indirectly concerned with respiration; not much, pro¬ 
bably, in undisturbed breathingbut when respiration is quick¬ 
ened, as in rapid progression, or from any other cause, we plainly see 
• how much the motions of the tongue are influenced, and especi¬ 
ally in those animals in which it is only slightly confined by the 
franum. The tongue of the horse is somewhat closely tied down 
by the frsenum, that it may constitute a convenient and .firm 
cushion for the bit; but where it is freer, as in the ox, and es¬ 
pecially in the dog, if the breathing is a little hurried, the tongue 
is protruded from the mouth, and, in the dog, is in constant mo¬ 
tion. The connexion of this with the mechanical act of respira¬ 
tion has been explained in a former lecture. 
Conclusion with regard to the Function of these Nerves.— -Then 
I begin to form some idea of the intention and function of these 
nerves from the lateral column distributed to the tongue. They 
are designed to call into action,_ and to combine together, the 
muscles of the tongue for the discharge of two important func¬ 
tions, as well before the mind could determine their action, as 
afterwards, when it had power to do so, but was in a manner un¬ 
conscious of whit took place; and also when, under unusual cn- 
cumstances, it was necessary to add another and a stronger in- 
