566 



SCIENCE. 



[N. S. Vol. I. No. 14. 



more enormously valuable as improvements 

 iipon current methods than was the inven- 

 tion of the modern steam-engine and the dis- 

 placement of the old machines of Worcester 

 and Savery. It is also possible that nature's 

 waj'S of producing light and electricity, as 

 well as power, may be ultimately found 

 immensely more economical than those of 

 man. They certainly are quite different, 

 and are inconceivably more ef&cient in 

 themselves, as single transformations, than 

 any processes yet discovered by science. 

 In the second place, the laws of operation of 

 the vital machine being fully revealed, it is 

 possible that we may find ways of promot- 

 ing the improvement of the machine in 

 such a manner as to make the animal 

 mechanism a mox-e ef&cient and a better 

 apparatus for the use of man, and even, 

 perhaps, find ways of improving the instru- 

 ment employed by the mind in its special 

 operations, as well as the mechanism of the 

 frame in which it is given a home and a 

 vehicle. 



The outcome of the investigations made 

 up to the present time may be stated 

 perhaps in the briefest and most intelligible 

 way in the form of a series of theorems, 

 thus: 



(1.) The Vital Machine is not a thermody- 

 namic engine, a heat-motor. 



Many writers have taken for granted the 

 now obviously incorrect hypothesis that, 

 since the machine is evidently a source of 

 heat, and its energy is derived from com- 

 bustible materials, it must, therefore, be a 

 heat-engine and its operations necessarily 

 thermodynamic. This is easily disproved. 

 In any thermodynamic machine, of whatever 

 class, among the heat- motors, the proportion 

 of heat converted into work, the ' efficiencj' ' 

 of the machine is measured by the range of 

 temperature, from the highest to the lowest 

 in the cycle operated in by the thermody- 

 namic mechanism, divided by the maximum 

 absolute temperature in the cycle. For the 



animal machine this would ordinarily be 

 the widest range of temperature attainable 

 in thermodynamic conversion divided by 

 about 300° C. But the machine is, in- 

 this case, a mass of circulating fluids of lair 

 condiictivity, mainly, and can have no sen- 

 sible range of temperature, so far as can be 

 seen ; and, in fact, it is known that differ- 

 ences of but one or two degrees, in different 

 parts of the bodj', the only actual diflfer- 

 ences of temperature, are produced by a 

 slight warming of the venous blood by 

 chemical action, or by proximity to or dis- 

 tance fi-om the epidermis. As a thermody- 

 namic engine, even were it possible, there- 

 fore, the machine should have an exceed- 

 ingly low efficiency. The fact is that its 

 efficiency exceeds that of any heat-engine 

 known to man, under the most favorable 

 possible practical working conditions. 



The vital engine is certainly not thermo- 

 dynamic ; its heat is a ' bj^-product.' 



(2.) The machine is jprohahly not electro- 

 dynamic. 



Scoresby and Joule, and Sir William 

 Thomson ' Lord Kelvin ' and others among 

 later writers, have suggested that the ma- 

 chine may be, as some have said, an electi'o- 

 dynamic machine, others an electro-mag- 

 netic engine. In support of this view it is 

 pointed out that, in some cases, as in the 

 gjonnotus, the torpedo and some fiftj' otlier 

 creatures, powerful electric batteries, accum- 

 mulators, are found in the animal system; 

 that all animals seem to have conductors, 

 the nerves, and that electricity leakage is 

 alwaj^s to be detected in the living creature 

 — currents passing in various directions 

 through the body and leaking outward to 

 the surface in all parts. The nerves termi- 

 nate in ' plates ' having close relation in 

 form and structure to the more highly de- 

 veloped cells of the storage batteries of the 

 eel and similar animal producers of elec- 

 tricitJ^ 



A great variety of facts and cousidera- 



