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XI PHENOMENA OF ORGANIC NATURE 317 
the force of gravity which it overcomes? Or, if 
you go to more hidden processes, in what does the 
process of digestion differ from those processes 
which are carried on in the laboratory of the 
chemist ? Even if we take the most recondite 
and most complex operations of animal life—those 
of the nervous system, these of late years have 
been shown to be—I do not say identical in any 
sense with the electrical processes—but this has 
been shown, that they are in some way or other 
associated with them; that is to say, that every 
amount of nervous action is accompanied by a 
certain amount of electrical disturbance in the 
particles of the nerves in which that nervous 
action is carried on. In this way the nervous 
action is related to electricity in the same way 
that heat is related to electricity ; and the same 
sort of argument which demonstrates the two latter 
to be related to one another shows that the nervous 
forces are correlated to electricity ; for the experi- 
ments of M. Dubois Reymond and others have 
shown that whenever a nerve is in a state of 
excitement, sending a message to the muscles or 
conveying an impression to the brain, there is a 
disturbance of the electrical condition of that 
‘nerve which does not exist at other times; and 
‘there are a number of other facts and phenomena 
of that sort; so that we come to the broad con- 
clusion that not only as to living matter itself, but 
as to the forces that matter exerts, there is a close 
