92 Dr. A. P. W. Philip on the 
of Mr. Charles Bell, which have afforded new and important 
views of the distribution and uses of certain nerves *. 
A set of functions still remains to be considered, which will, 
' I think, be found equally distinct from those of the muscular 
and nervous systems, although they have never been correctly 
distinguished from the lattert. I allude to the sensorial func- 
tions, the maintenance of which seems to be the final cause of 
both the others. The functions of the muscular and nervous 
powers maintain the life and health of the animal, and are the 
immediate means of intercourse between it and the external 
world; by those of the sensorial power it is rendered capa- 
ble of enjoyment. Were this, however, the only object of that 
power, it would not fall under the scope of the present paper, in 
which it is proposed to consider the vital powers alone. But 
on minute inquiry into the relation which the various functions 
of the more perfect animals bear to each other, it will appear 
that the sensorial functions are necessary to the existence of 
the rest. It is only, as was stated at the beginning of this 
paper, in as far as they are so, that we are here to consider 
them. 
The first observation which strikes us on comparing the 
nervous functions, which we have been considering, with those 
termed sensorial, is that the former bear a striking, the latter 
no, analogy to the effects observed in inanimate nature. The 
excitement of the muscular fibre, the act of secretion, and the 
maintenance of animal temperature, bear a striking analogy to 
the processes of the laboratory, and the transmission of impres- 
sions through the nerves, both to chemical and mechanical pro- 
cesses; but what analogy can we detect between the functions 
of the sensorial power, sensation and volition, for example, and 
such processes. We are now in a new world, and we at once 
* Philosophical Transactions for 1821. 
+ The circumstance of the sensorial and nervous functions having never 
been accurately distinguished, appears to have been a priucipal cause of 
the nature of the latter being involved in so muck obscurity. , 
The term vital principle has been used with so little precision, that I 
must beg the reader to keep in view the definition of it given in the com- 
mencement of this paper. 
