370 
DR. PHILIP ON THE POWERS OF LIFE. 
the one I attempted to ascertain what functions remain when the sensorial powers 
are withdrawn ; by the other, what functions fail with the failure of the nervous 
powers ; and the correspondence of the results of these sets of experiments tends to 
confirm the inferences from both *. 
Much confusion had arisen from physiologists having neglected to ascertain this 
line. M. le Gallois, one of the most acute, soon found his difficulties from this cause 
such, that he was obliged to confess himself unable to proceed, and leave to his suc- 
cessors the task of removing them. He had adduced sufficient proof of the spinal 
marrow, to which the nerves of respiration belong, being capable of its functions 
independently of the brain ; yet on the removal of a part of the brain, the medulla 
oblongata, respiration ceases. This difficulty he acknowledges he sees no means of 
removing, calling it 44 un des grands myst&res de la puissance nerveuse, mystere qui 
sera devoile tot ou tard, et dont la decouverte jettera la plus vive lumiere sur le me- 
chanisme des fonctions de cette merveilleuse puissance.” 
If the preceding facts be kept in view, it is evident without much consideration that 
none of the functions of the sensitive have any other dependence on the powers of 
the vital system, but for the due structure and wellbeing of their organs. The nature 
of the functions of the vital system here requires more consideration. They include 
respiration ; circulation ; those processes by which the secreted fluids are formed ; 
those, namely the more immediately assimilating processes, by which our food is con- 
verted into the various organs of our bodies, and such parts of them as have become 
unfit for the purposes of life are separated and expelled, for all are in a state of 
change ; and those by which the due temperature is maintained. 
Does the sensitive cooperate with the vital system in any of these functions ? 
From the line of distinction, determined by the experiments just referred to, it 
appears that in one of them only is there such a cooperation. 
I have in the last of my papers published in the Philosophical Transactions for 
1 829 considered at length the nature of respiration, and have, as far as I am capable 
of judging, adduced such facts as prove that the muscles employed in this function 
are, in the full sense of the word, muscles of voluntary motion. The first act in 
respiration is the impression made on the sensorium, the sensation excited by the 
want of fresh air in the lungs. We are enabled to supply it and remove the uneasi- 
ness, by exciting, through the nervous system properly so called, certain muscles 
subject to the will. 
Respiration thus depending on the combined operation of both systems, is as effec- 
tually destroyed by a failure of the sensation which makes us will to inspire, as by that 
of the nervous or muscular power by which the will effects its object. Thus the diffi- 
culty of M. le Gallois disappears. It is true that the spinal marrow and its nerves 
are capable of their functions independently of the brain, and that the nerves employed 
in respiration are supplied by the spinal marrow, but in this function it is an act of 
* Inquiry into the Laws of the Vital Functions, Part II. 
