488 FRAGMENTS OF SCIENCE. 



that labourer's work exerted on the muscles alone, they 

 would be utterly consumed in 80 days. The heart 

 furnishes a still more striking example. Were the 

 oxidation necessary to sustain the heart's action exerted 

 upon its own tissue, it would be utterly consumed in 8 

 days. And if we confine our attention to the two 

 ventricles, their action would be sufficient to consume 

 the associated muscular tissue in 3-J days. Here, in his 

 own words, emphasised in his own way, is Mayer's 

 pregnant conclusion from these calculations: 'The 

 muscle is only the apparatus by means of which the 

 conversion of the force is effected ; but it is not tlie 

 substance consumed in the production of the mecha- 

 nical effect.' He calls the blood ' the oil of the lamp of 

 life;' it is the slow-burning fluid whose chemical force, 

 in the furnace of the capillaries, is sacrificed to produce 

 animal motion. This was Mayer's conclusion twenty-six 

 years ago. It was in complete opposition to the scien- 

 tific conclusions of his time ; but eminent investigators 

 have since amply verified it. 



Thus, in baldest outline, I have sought to give some 

 notion of the first half of this marvellous essay. The 

 second half is so exclusively physiological that I do not 

 wish to meddle with it. I will only add the illustration 

 .employed by Mayer to explain the action of the nerves 

 upon the muscles. As an engineer, by the motion of his 

 finger in opening a valve or loosing a detent, can liberate 

 an amount of mechanical motion almost infinite com- 

 pared with its exciting cause, so the nerves, acting upon 

 the muscles, can unlock an amount of activity, wholly 

 out of proportion to the work done by the nerves them- 

 selves. 



As regards these questions of weightiest import to the 

 science of physiology, Dr. Mayer, in 1845, was assuredly 

 far in advance of all living men. 



