TPIOUGHTS ON THE NATURE AND ORIGIN OF FORCE. 247 



A demonstration of this is seen in the case of luo tor-paralysis, (\Yhich 

 may be likened to the state of a steam-engine ^yith the cylinder-valves 

 locked in position, or detached from the eccentric,) or in the case of 

 that extreme prostration which follows a low fever or prolonged illness, 

 (which may be likened to the condition of an engine whose head of 

 steam is insufficient to overcome the inertia of the piston.) 



But not only the animal processes of nutrition, growth, and movement 

 are maintained ab extra, but those more subtle and mysterious processes 

 of thought, emotion, reason, are alike the product of inaterial metamor- 

 phosis ; and their activities may be determined by the urea and the 

 phosphates, and even phosphoric acid, eliminated by the kidneys. A 

 large-brained man sitting idly in his easy-chair, with eyes closed to ex- 

 ternal impressions, and indulging in pleasant revery, might seem to be 

 the very impersonation of self-contained and self- originating action. 

 But apart from the chemical tests alluded to, which would demon- 

 strate the fact of matter potential, undergoing a descent, we may 

 employ the more direct and delicate indicator, a thermogalvano- 

 meter, in connection with the baek part of the dreamer's head, and we 

 shall observe the needle to quiver and to fluctuate with the current of 

 the varying thought. Let a knock be heard at the door, and though no 

 movement of the face, no tremor of the closed eyelid betrays to the ob- 

 server a consciousness of the sound, yet this tell-tale needle (sensitive 

 to the two-thousandth x)art of a degree Fahrenheit) will attest by a 

 deflection, of many degrees of arc the aroused attention involuntarily 

 excited through the action of the auditory nerves.* Here, then, we 



point, it may be remarked that our faith iu the doctrine of the constancy of force need 

 not be shaken by this sole outstanding difficultj^, or apparent limitation of its univer- 

 sality; and that however unable Ave may now be to explain or suggest the hoiv — this 

 last residuum, " will-power," (admittedly very small relatively to the product of volun- 

 tary force,) as well as that organic-]iower which determines that from the equal stores 

 of force laid up in the two eggs of a duck and of an alligator, or of a dove and of a ser- 

 pent, the one shall be directed to evolve a bird and the other a reptile — may yet be hero- 

 after referred to the magazines each serves to unlock, or else to a principle entirely 

 outside of mechanical force. 



* In an interesting account of " Experiments on the Relation of Heat to Mental 

 Work," by Professor J. S. Lombard, M. D., of Harvard University, employing a galvan- 

 ometer capable of indicating about the live-hundredth part of one degree Fahrenheit 

 it is stated that the ordinary variations observed resulting from mental action did not 

 amount to more than about the fiftieth of a degree, though quite marked. " Pursuing 

 these experiments farther, it was found that anything that aroused the attention was 

 capable of causing a greater or less rise of temperature on the i)art of the head, over 

 and above that of the body." With the exercise of the higher reasoning powers, " the 

 highest rise noticed did not exceed the twentieth of a degree," (about one-eleventh of a 

 degree Fahrenheit,) while "the temperature of the extremities fell." " The most striking 

 effects of all were ]5roduced by the reading aloud or the recitation of j)oetry." " Read- 

 ing or reciting to one's self gave similar results, and often even iu a more marked de- 

 gree." " In the last-mentioned series of observations, it was not unfrequently found 

 that the temperature of the forehead fell, while that of the back of the head rose ; but 

 for what reason, I have not yet been able to determine." ( The Nciv Torlc Medical Journal 

 for June, 1867, Vol. V. pp. 198-205.)" 



