332 THE ANIMAL AS A PRIME MOVER. 



familiar forms of electricity. It is well known that muscular power 

 may reside in the muscle, and that this local potentiality of energy dis- 

 play may be exerted by, and may even act rhythmically in, an organ, 

 as the heart, detached from the body. 



Light production by the vital machine illustrates another curious and 

 impressively suggestive method of energy transformation, the nature 

 of which, and the essential prerecprisites for which, are still among the 

 mysteries of this ever-present sphinx. 1 The light radiated by the 

 living machine has been studied by many investigators, and something 

 has been learned of its production and its characteristics. It is known 

 to be produced in a superficial, transparent tissue, blanketing the parts 

 of the creature exhibiting luminosity, and containing a fat of peculiar 

 structure and composition, which may be burned at extraordinarily low 

 temperatures, giving out a light almost absolutely free from heat. It can 

 thus be utilized in the animal system and, only light being produced, 

 but a minute fraction of the energy demanded in the production of our 

 more familiar lights is required for this transformation. In its distri- 

 bution but a fraction of 1 per cent of the energy thus expended takes 

 the form of heat, while in the common gas, or candle, or oil flame 99 

 per cent of the energy is wasted in the form of heat; worse than 

 wasted, since the heat thus produced is usually a source of discomfort 

 as well as a material loss. 



The vital machine, as a light producer, thus appears to have an 

 efficiency of production approximating unity. 2 It has 400 times the 

 light value of the gas flame, 40 times that of the electric incandescent 

 lamp, and *20 times that of the best arc lamp. But the electric current 

 utilized in these cases is derived from heat energy transformed by the 

 heat engine and the dynamo at, usually, the expense of four-fifths to 

 nine-tenths its original potential amount; thus making the light of 

 nature, as developed in the vital machine, from 200 to 4,000 times as 

 efficient as the best and the worst, respectively, among our present 

 artificial lights, if we assume no wastes in the production of the light- 

 giving material. This would be the case if, for example, its wastes of 

 energy, were there any to occur in the process, were to find use in fur- 

 ther transformation, or application, in the economy of the system, as 

 the heat of the exhaust steam of a steam engine in a woolen mill 

 often has as great value for heating purposes as if taken direct from 

 the boiler. Could this kind of light be obtained as the product of 

 artificial methods of energy transformation, the result in economy 

 of energy, of power, and of fuel would be among the most tremendous 

 of all the marvelous products of human invention. 



Technically stated, the problem is: to produce ether vibrations hav- 

 ing a frequency of 5 x 10 14 per second, without admixture of other 



1 The Great Problems of Science. R. H. Thurston. Foruni, September, 1892. 

 -Laiigley and Very, on the Heat and Light of the Fire-ily. Smithsonian Contri- 

 butions to Knowledge, 1892. 



