4 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



movement so that the largest amount of movement might be 

 performed at the least possible expense. What one can actually 

 do is something very far short of this, but still perhaps sufficient 

 to indicate that systematic knowledge of the kind required 

 is not out of reach. I am, for instance, only able to talk about 

 two kinds of movement ; having to exhibit on the one hand 

 some information gained from a study of the expense of cycling, 

 performed as on the ordinary " push-cycle," except in so far 

 that the resistance encountered was not that of the wind and 

 road, but that of a " brake," which could be applied to any 

 required degree and maintained in uniform action ; and on 

 the other hand having also something to say about the expense 

 of walking, in this case against so little resistance as is en- 

 countered " on the grass at Oxford " (Douglas and Haldane). 

 Now, perhaps, not true of walking, but certainly in the 

 case of cycling (under the conditions examined) there is no 

 difficulty in measuring all the external work done. This obtained 

 value may then very readily be arranged on one side of a 

 balance sheet, and on the other side it is possible, as will be 

 briefly explained, to state the total expense incurred in gaining 

 this value. However, this statement would not be a really 

 useful return of gain and loss, and obviously so since it is clear 

 that the process of " cycling " would be even still more advan- 

 tageous if the external work done was reduced to a negligible 

 quantity — although then, according to the method of arranging 

 the account as described, there would seem to be no value 

 gained — since movement would then be facilitated and pro- 

 portionately a greater distance covered, a greater amount of 

 locomotion secured. That is to say, that in addition to the 

 external work performed on masses external to the worker, 

 there is also to be considered the work done upon his own 

 limbs and body, and the value obtained in their motion. 

 However, this latter tale of work is at the present time not 

 capable of exact expression as so many units of work, so many 

 foot-pounds or kilogrammemeters, or as so many comparable 



