FREEMAN, W. J. 
organized into a series of nuclear masses, which provided the ana- 
tomical substrate for 'centers.' A second" important influence was 
the continuing wide-spread interest in phrenology, which was kept 
before the public in the more acceptable form of localization of 
mental processes by the writings of Herbert Spencer. This implied 
that particular functions, which could be observed holistically in 
behavioral context, could be ascribed to particular parts of the 
brain. 
A less direct, more subtle, and yet equally important influence 
was the developing science ofthermocfynamics. This has been intro- 
duced earlier by Johannes Miiller in his law of specific nerve ener- 
gies. Throughout this time nerve discharges were described in 
physical terms such as nerve force or nerve energy. For example, 
Spencer (1863) stated (quoted from Darwin,1872, p. 109) as an 
"unquestionable truth that, at any moment, the existing quantity of 
liberated nerve-force, which in an inscrutable way produces in us 
the state we call feeling must expend itself in some direction — 
must generate an equivalent manifestation of force somewhere." 
This is a statement of conservation of momentum. Darwin (1872) 
remarked: "This involuntary transmission of nerve force may or 
may not be accompanied by consciousness. Why the irritation of 
nerve-cells should generate or liberate nerve force is not known; 
but that this is the case seems to be the conclusion arrived at by 
all the greatest physiologists such as Miiller, Virchow and Bernard, 
and so on." (Darwin, 1872, p. 70). 
As originally stated by Miiller, this hypothesis proposed that 
packets of vital fluid travelled down nerves at immeasurable speed. 
This was subsequently disproven through studies by Helmholz, 
Hermann, and others on the action currents of peripheral nerve and 
was finally discredited by the clear distinction that came to be 
drawn between vital spirits and electricity. In its place was intro- 
duced the notion of a unit or quantum of electro-chemical energy, 
the action potential, as the sole vector of information in the nervous 
system, with the sole attributes of number and location in time and 
space. 
These units of energy were thought to summate algebraically, 
in space andtime, and when concentrated in a local volume of tissue, 
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