104 Dr. A. P. W. Philip on the 
of the nervous system, and the chemical processes which take 
place in such matter ; and if an inanimate agent be employed in 
these processes, its supply and application must be regulated by 
the vital powers of the nervous system. Whether this agent be 
a distinct being, or only a peculiar modification of the particles 
of bodies, is not the question; all the essential inferences are, in 
either case, the same. The phenomena of electric animals are 
here in point. We see their nervous system collecting and ap- 
plying, even according to the dictates of the will, an manimate 
agent. 
While these observations point out the necessity of limiting 
our study of the sensorial functions to a careful observation and 
arrangement of their phenomena, they encourage us to inquire 
into the nature of the functions of the nervous power ; that is, to 
endeavour to refer them to some more general law, whose phe- 
nomena, however modified, are not wholly changed by one of the 
agents in these functions being endowed with the vital principle. 
The power which operates in many other instances may be the 
means of exciting the muscles, of conveying impressions to and 
from the sensorium, of effecting the formation of the secreted 
fluids, and of maintaining the temperature of the animal body. 
The most subtile of known agents, electricity, naturally suggests 
itself, and when voltaic electricity and its signal influence on the 
muscular system were discovered, a material step, it was ima-~ 
zined, had been made towards ascertaining the nature of the 
nervous power. On more mature reflection, however, it was 
admitted, that to ascertain that galvanism is capable of exciting 
the muscular fibre, is to go but a very short way towards esta- 
blishing its agency in the phenomena of the nervous system, a 
very large proportion of bodies possessing the same property ; 
and of late the opinion appears to have been abandoned ; nor 
can it be maintained on any other grounds than by showing that 
this species of electricity is capable of the more characteristic, as 
well as the more simple, functions of that system. On comparing 
the properties of galvanism with the phenomena of the nervous 
system, the analogy between them seemed to me to warrant the 
investigation thus suggested. 
