602 MR. youatt’s veterinary lectures. 
I then proceeded to that kindred and newly-discovered power, 
newly discovered, at least, with regard to its function, and the 
discovery of which will immortalize the name of Bell—(on no 
scientific man was ever an honorary distinction more worthily con¬ 
ferred by his sovereign)—the respiratory nerves ; derived from the 
lateral column of the medulla oblongata and the spinal chord ; 
immediately on their escape from the skull, closely connected 
with the ganglionic, anastamosing freely with them, associated 
with them in function, and, at length, perfectly mingling and 
identified with them. 
These constitute another fountain of organic life, prior, how¬ 
ever, to their perfect amalgamation with the ganglionic, some¬ 
what differing in function,—acting when the animal is unconscious 
of the action, and in despite of the will, yet, to a certain degree, 
under its influence and control, and sensitive only as connected 
with the ramifications of the sensitive nerves of the spinal 
column:—interposed between the nerves of voluntary motion and 
sensation—a kind of neutral ground between them—deriving 
assistance from or leading it to the cerebral nerves-—proceeding 
first, as their names imply, to the respiratory organs, but not 
terminating there—either directly or indirectly conveyed to, and 
influencing every viscus of organic life. 
Having considered the functions of the nerves, I entered on the 
consideration of their diseases, whether referrible to excessive, 
or diminished, or irregular, or suspended influence, including 
tetanus, rabies, epilepsy, palsy, chorea, and various other affec¬ 
tions. 
Then, as the stimulus presupposed a tissue to be acted upon, 
and in that tissue a power of responding to the action of the sti¬ 
mulus, a principle of contractility; and as that which was first 
of all, or exclusively necessary to the existence or continuance of 
this contractility was a constant and due supply of arterial blood, 
I was led to the circulatory system,—the mechanism of 
the circulation,—the power by which the blood was propelled, 
and the vessels through which it flowed. 
I considered the construction of the central machine,—its per¬ 
cussive action,—that by which, in some of the grander as well as 
simpler operations of nature and of art, power is so astonishingly 
multiplied. I followed the blood through the arterial system:— 
these vessels, in the natural and healthy state of the circula¬ 
tion, seemed to be mere mechanical tubes, yet, under disease 
or derangement they were capable of exerting a controlling 
influence, and could supply a defect of power in the central ma¬ 
chine, or neutralize its too energetic action. Ramifying from 
