408 
MR. YOUATTS VETERINARY LECTURES. 
involuntary action ,—a pure organic one ;—and a diligent observa¬ 
tion of the mechanism of respiration will render it highly probable 
that it is so. 
Difficulty as to its Origin .—How, then, shall we account for 
its origin as a true spinal nerve, curiously made up of fibrils from 
different nerves, but all to be traced to the columns of animal 
sensation and voluntary motion? This is a difficulty which no 
anatomical fact will enable me to surmount; and to relieve my¬ 
self from it, I am obliged to have recourse to that which is uti- 
philosophical, and rarely, indeed, admissible,—the supposition of 
that which I cannot prove, that when, from a better process of 
maceration or hardening, we are able to unravel the complicated 
fibres of the spinal chord, it may hereafter appear that certain 
portions of the fifth, the sixth, and the seventh cervical nerves are 
derived from the lateral column, or that w r hich is connected with 
the functions of organic life. Until then we must rest content 
with the undeniable fact, that the phrenic nerve is, in the ordi¬ 
nary distribution of its influence, a purely organic one; and the 
strong inclination of my belief is, that it is only indirectly that 
it can be ever brought under the power of the will. It acted 
before a volition could be formed; it continues to act when the 
mind is passive; and it is only by opposing a superior power, and 
by the combination of many a muscle, that the will has any con¬ 
trol over it. There are stages, and states, and modifications of 
the respiratory function, which are necessarily to a great degree 
subjected to the influence of the will. If I were to select alone 
the faculty which every animal possesses of communicating his 
ideas, or expressing the pleasure or the pain which he feels 
through the medium of the voice, I should have a sufficient 
illustration of the association of voluntary pow r er with the organic 
principle, in a way which neither the function of circulation or 
digestion, and, in fact, which no other function can require. 
Hence arises the difficulty; but a difficulty which is resolved by 
the observation, that the discharge of the function, so far as it is 
essential to life, depends on the organic principle ; and that the 
intervention of the will is permitted only when our occasional 
u comfort or accommodation ” requires it. But, gentlemen, I am 
here again theorizing somewhat too much. We have one more 
nerve, and that a most important one, to describe ; and then 
neither you nor I shall be sorry to return to that which ought to 
be the main object of our anatomical and physiological researches, 
and which gives them their highest, and, comparatively speaking, 
their onlv value,—a consideration of the nature and treatment of 
disease. 
