DR. PHILIP ON THE POWERS OF LIFE. 
351 
The nerves of sensation in which are included, of course, the nerves of the external 
senses, and the immediate organs of the sensorial powers are not parts of the same 
organ, but distinct parts, having different localities and performing functions of a 
wholly different nature ; that is, the sensorium does not pervade the whole system, 
but belongs to particular parts. To what parts has never been correctly ascertained, 
but we know that in man they are confined to certain parts of the brain with little if 
any participation by the spinal marrow ; although in some of the inferior animals the 
spinal marrow largely partakes of them, a proof that the sensorium is not as some 
have supposed confined to a physical point, but is of a considerable extent. 
Our sensations are referred to certain parts of the body by experience alone. Hence 
the well-known facts that infants are not aware of the part of the body in which the 
cause of any sensation originates ; and when a limb has been lost, at whatever part 
the separation is made, we continue to refer to the lost part sensations excited by 
causes affecting the nerves of the stump. 
The function of the nerves of sensation has relation to the sensorial organs alone. 
The influence they convey is the means by which the sensorium is impressed by 
distant parts, and such is their only function. 
The more perfect animals then possess four distinct powers, having no direct de- 
pendence on each other, but each we shall find indirectly dependent on the other 
three, namely for the maintenance of its organs. 
I am now to inquire how far we can advance in determining the nature of these 
powers, how far they are peculiar to the living animal, or the same which operate in 
other parts of nature. 
WE are in the habit of regarding life as a power of peculiar mystery, but do we 
find any other principle of action less mysterious ? It is not the principle but its pro- 
perties, which are the objects of our senses. A knowledge of the former is not merely 
beyond the limits, but the nature of our minds. Do we know more of the principle 
of electricity or gravitation than of life, or is there more uncertainty in noting the 
property of resistance to fermentation and congelation without any sensible pecu- 
liarity in the substances possessed of this property, than that of weight or light ? It 
is not that the nature of life is more obscure than that of any other principle of 
action, all are equally so, but that its phenomena, being more varied and bearing 
less analogy to those of other principles than these bear to each other, are less fa- 
miliar objects of contemplation. 
The subject thus appears invested with an obscurity which does not belong to it, 
and the perplexity has been increased by vain attempts to remove it ; attempts on 
principles having no relation to the laws by which the phenomena of life are regu- 
lated. What possible relation can the laws of mechanics, or any other principle 
which operates in the inanimate world, bear to the phenomena of life properly so 
called ? It is as much a distinct principle as any of those which operate in that 
