THE SOURCE OF NERVE FORCE. 75 
11. ON THE SOURCE OF NERVE FORCE: A THEORY.* Page 251. 
THE universally acknowledged inefficiency of any theory at present 
before the scientific world to account for the origin of the force by 
which, through the intervention of the nervous system, organs at a 
distance from one another are placed in communication, makes me 
feel justified in publishing a theory which has been in my mind for 
some time, and which during that time accumulated information has 
not in any way shaken. 
' The following is my proposition:—The species of energy which 
exhibits itself in the form of “ nerve force,” is electricity of thermo- 
electric origin, resulting from the fact that the surface of the living 
animal body is always colder than its interior. In other words, the 
available energy resulting from the interior of the living animal body 
being at a higher temperature than that of the surrounding medium, 
is expended wholly, or in great measure, in generating the force called — 
nerve force. In the discussion of this problem, the following are the 
considerations on which it is based. 
1. The temperature of the interior of the living body is always 
"greater than that of its surface, because all animal life is only a form 
of chemical degradation, and is therefore necessarily attended with 
evolution of heat; which, no other force intervening, will always keep 
the interior of the body hotter than the medium in which it lives. 
When the temperature of the air in higher animals exceeds or nearly 
approaches that of the body, which varies but little, special arrange- 
ments (perspiratory, &c.) come into play to diminish that of the 
surface. 
2. There is an available source of energy in the body, which has 
been but little considered by physiologists, depending on the tempera- 
ture of the surface being lower than that of the interior. The theory 
propounded gives employment for this force. r 
3. In the struggle for life, the individuals that economise -the 
forces at their disposal are most likely to survive; it is therefore im- Page 252. 
probable that this not inconsiderable source of energy should have 
escaped employment in this struggle. 
4. The actual construction of the nervous system is quite sufficient 
for the working of such a force as the one proposed. In addition to 
the already known properties of the nerves, including their good con- 
ducting power, it is only required that a thermo-electric current be cap- 
* “ Journal of Anatomy and Physiology,” VII. pp. 251-4. June, 1873. 
