DR. PHILIP ON THE POWERS OF LIFE. 
357 
tests. A correct chemical test will give evidence of what we are in quest of under all 
circumstances ; and is therefore capable in all instances of detecting its presence, and 
consequently its absence also. This arises from there being but one counteracting 
power, that of affinity. If the affinity be stronger in the test than in any other sub- 
stance, the effect of all other affinities is destroyed. We possess no such electric test, 
because here there may be other counteracting causes beside the power of affinity, 
opposing currents, for example. Besides, we know that the properties of electricity 
are so modified by the powers of life, as greatly to interfere with its relations to our 
tests. The electricity of the torpedo and other electric animals does not affect the 
common electrometer, yet no one has doubted its identity with the electricity of in- 
animate nature. 
Although electric tests therefore give evidence of the presence of electricity, we 
cannot by their means prove its absence ; a fact with which we should not have been 
acquainted, were it not, under certain circumstances, possible to prove the presence 
of electricity without their aid ; that is, the presence of electricity may under certain 
circumstances be proved, where it is not indicated by any of the properties generally 
admitted to be peculiar to it. 
Suppose it were said, for example, that we cannot admit that electricity is the agent 
in the combination of oxygen and carbon, because there is no test by which its pre- 
sence can be detected ; the reply of Dr. Faraday, 1 conceive, would be ; we cannot 
at present, whatever we rnay do hereafter, make the electricity employed in effecting 
this combination evident to any of our tests ; but I consider its presence as a necessary 
inference, because I have adduced facts which prove, either that electricity is the 
agent in such combinations, or that nature here deviates from the simplicity observed 
in all her other works. Either electricity is the agent in the combination in question, 
or there are two kinds of chemical affinity. 
Under such circumstances can any other reply avail except either disproving the 
facts or pointing out the fallacy of the inference ? 
What I have done is strikingly illustrated by the late investigations of Dr. Faraday. 
It is more than twenty years since I found that voltaic electricity is capable of all the 
functions of the nervous influence ; it now appears from the facts, on which he has 
founded his doctrine of electro-chemical equivalents, that electricity is the agent in all 
chemical processes*. According to the inferences of Dr. Faraday therefore, the ex- 
periments, which prove that the nervous influence is the agent in the functions we 
have been considering, all of which we have seen are chemical processes, are sufficient 
to prove its electric nature ; and we are now also, on the other hand, furnished with 
direct proof that the brain is capable of collecting and applying, even according to 
the dictates of the will, the electric power. 
Dr. Davy in his last paper on the torpedo-^ observes that, “ when the brain has been 
* Dr. Faraday’s papers in the Philosophical Transactions for 1832, 1833, 1834, and 1835. 
t Philosophical Transactions for 1834. 
