ii8 APHORISMS AND REFLECTIONS 



passes in and out with the flow and the ebb of the 

 respiratory tide. Mechanically, this act of drawing 

 breath, or inspiration, is of the same nature as that 

 by w^hich the handles of a bellows are separated, 

 in order to fill the bellows with air ; and, in like 

 manner, it involves that expenditure of energy 

 which we call exertion, or work, or labour. It is, 

 therefore, no mere metaphor to say that man is 

 destined to a life of toil : the work of respiration 

 which began with his first breath ends only with his 

 last ; nor does one born in the purple get off with a 

 lighter task than the child who first sees light under 

 a hedge. 



How is it that the new-born infant is enabled to 

 perform this first instalment of the sentence of life- 

 long labour which no man may escape ? Whatever 

 else a child may be, in respect of this particular 

 question, it is a complicated piece of mechanism, 

 built up out of materials supplied by its mother ; and 

 in the course of such building-up, provided with a set 

 of motors— the muscles. Each of these muscles 

 contains a stock of substance capable of yielding 

 energy under certain conditions, one of which is a 

 change of state in the nerve-fibres connected with it. 

 The powder in a loaded gun is such another stock of 

 substance capable of yielding energy in consequence 

 of a change of state in the mechanism of the lock, 

 which intervenes between the finger of the man who 

 pulls the trigger and the cartridge. If that change 

 is brought about, the potential energy of the powder 

 passes suddenly into actual energy, and does the 

 work of propelling the bullet. The powder, there- 

 fore, may be appropriately called work-stuff, not only 

 because it is stuff which is easily made to yield work 

 in the physical sense, but because a good deal of 

 work in the economical sense has contributed to its 

 production. Labour was necessary to collect, 

 transport, and purify the raw sulphur and saltpetre ; 

 to cut wood and convert it into powdered charcoal ; 

 to mix these ingredients in the right proportions ; to 



