SCIENCE AND MAN 



has been described by a competent 

 authority as " the grandest of all." I 

 subscribe to this opinion, and honour 

 correspondingly the man who first suc- 

 cessfully grappled with the problem. 

 He was no pope, in the sense of being 

 infallible, but he was a man of genius 

 whose work will be held in honour as 

 long as science endures. I have already 

 named him in connection with our 

 illustrious countryman Dr. Joule. Other 

 eminent men took up this subject subse- 

 quently and independently, but all that 

 has been done hitherto enhances instead 

 of diminishing the merits of Dr. Mayer. 

 Consider the vigour of his reasoning. 

 " Beyond the power of generating in- 

 ternal heat, the animal organism can 

 generate heat external to itself. A 

 blacksmith by hammering can warm a 

 nail, and a savage by friction can heat 

 wood to its point of ignition. Unless, 

 then, we abandon the physiological 

 axiom that the animal body cannot create 

 heat out of nothing, we are driven to the 

 conclusion that it is the total heat, within 

 and without, that ought to be regarded as 

 the real calorific effect of the oxidation 

 within the body." Mayer, however, not 

 only states the principle, but illustrates 

 numerically the transfer of muscular heat 

 to external space. A bowler who imparts 

 a velocity of 30 feet to an 8-lb. ball con- 

 sumes in the act one-tenth of a grain of 

 carbon. The heat of the muscle is here 

 distributed over the track of the ball, 

 being developed there by mechanical 

 friction. A man weighing 150 Ibs. con- 

 sumes in lifting his own body to a height 

 of 8 feet the heat of a grain of carbon. 

 Jumping from this height the heat is 

 restored. The consumption of 2 ozs. 

 4 drs. 20 grs. of carbon would place the 

 same man on the summit of a mountain 

 10,000 feet high. In descending the 

 mountain an amount of heat equal to 

 that produced by the combustion of 

 the foregoing amount of carbon is 

 restored. The muscles of a labourer 

 whose weight is 150 Ibs. weigh 64 Ibs. 

 When dried they are reduced to 15 Ibs. 

 Were the oxidation corresponding to a 



day-labourer's ordinary work exerted on 

 the muscles alone, they would be wholly 

 consumed in 80 days. Were the oxida- 

 tion necessary to sustain the heart's 

 action concentrated on the heart itself, 

 it would be consumed in 8 days. And 

 if we confine our attention to the two 

 ventricles, their action would consume 

 the associated muscular tissue in 3^ 

 days. With a fulness and precision of 

 which this is but a sample did Mayer, 

 between 1842 and 1845, deal with the 

 great question of vital dynamics. 



.In direct opposition, moreover, to the 

 foremost scientific authorities of that day, 

 with Liebig at their head, this solitary 

 Heilbronn worker was led by his calcu- 

 lations to maintain that the muscles, in 

 the main, played the part of machinery, 

 converting the fat, which had been 

 previously considered a mere heat-pro- 

 ducer, into the motive power of the 

 organism. Mayer's prevision has been 

 justified by events, for the scientific 

 world is now upon his side. 



We place, then, food in our stomachs 

 as so much combustible matter. It is 

 first dissolved by purely chemical pro- 

 cesses, and the nutritive fluid is poured 

 into the blood. Here it comes into con- 

 tact with atmospheric oxygen admitted by 

 the lungs. It unites with the oxygen as 

 wood or coal might unite with it in a 

 furnace. The matter-products of the 

 union, if I may use the term, are the 

 same in both cases, viz. carbonic acid 

 and water. The force-products are also 

 the same heat within the body, or heat 

 and work outside the body. Thus far 

 every action of the organism belongs to 

 the domain either of physics or of 

 chemistry. But you saw me contract 

 the muscle of my arm. What enabled 

 me to do so? Was it or was it not the 

 direct action of my will? The answer 

 is, the action of the will is mediate, not 

 direct. Over and above the muscles the 

 human organism is provided with long 

 whitish filaments of medullary matter, 

 which issue from the spinal column, 

 being connected by it on the one side 

 with the brain, and on the other side 



