THE RECURRENT NERVES. 
117 
pursues its course. Having arrived at the larynx, the ultimate 
distribution of its filaments is the same as that of the right re- 
current : they both supply the dilator muscles of the larynx — 
they both give sensibility to it — and they both anastomose with 
the superior laryngeal nerves, in order to maintain that balance 
of power which is necessary to the well-being of the animal. 
The general Function of the Recurrent Nerves . — We now, 
perhaps, are enabled to arrive at some satisfactory conclusion 
with regard to the singular retrograde course which these nerves 
pursue. They are designed, in conjunction with the superior 
laryngeal nerves, to govern the contractions and dilatations of 
the larynx. The larynx is a beautiful piece of mechanism, by 
which the entrance into the canal leading to the lungs is 
guarded, the passage of extraneous bodies prevented, and that 
quantity of air which the immediate wants of the animal may 
demand admitted. There is a powerful and a salutary principle 
prevading the whole of the frame, namely, sympathy; by the 
influence of which the functions of the different organs are so 
regulated and controlled, that the well-being of the whole is 
promoted and in a manner secured ; but for the perfection of a 
function connected not only with the well-being but with the 
very existence of the animal, something more than the power of 
sympathy with distant organs is required : there must be a direct 
connexion, in order to unite the different parts of the machine in 
consentaneous and healthy action. It is, therefore, not only a 
very important consequence, but it is the very object and design 
of the devious course which the recurrent nerve pursues, that the 
different portions of the respiratory apparatus are brought into 
immediate connexion with each other, and thus a salutary uni- 
formity in the action of each is secured. 
The inferior laryngeal nerve is connected with, or, rather, it 
directly influences, every motion and feeling of the trachea — of 
the transverse muscle — the interposed ligamentous muscular 
substance between the rings — and the sensibility of the whole of 
the lining membrane. By anastomosis with, or forming a part of, 
the pulmonary plexus, it is identified with the state of the bronchial 
tubes, and the bronchial membrane, the perviousness or imper- 
viousness of their minute ramifications, and the quantity of air 
by which the terminating cells are distended ; and, farther, by 
means of the cardiac plexus, the influence of the great central 
machine, whether in a state of excitation or of debility, is also 
communicated. The nerve also (the right recurrent nerve) by 
means of which all this important information is obtained, not 
only communicates with its fellow on the membrane of the larynx, 
but in the substance of every one of both the constrictor or dila- 
