THE ECONOMY OF MOVEMENT. / 



and because of its elaboration far the less elastic and less 

 readily adaptable to the study of expenses incurred in different 

 kinds of movement, so that one has been tied down to the 

 repetition of a certain smaller group of experiments. This is a 

 fact, however, not without advantage. 



I have dealt, then, with the general form of the two state- 

 ments, such as may be encountered on any of these "balance- 

 sheets," of value obtained and expenses paid. On the one side 

 so much, and such, movement, and so much external work 

 performed, the latter expressed perhaps most usually as so 

 many calories per second ; and on the other side so many 

 units of energy liberated, also expressed — since as a matter of 

 fact thus measured — as so many calories per second. However, 

 I should say at once that I have represented the procedure 

 adopted somewhat too simply. It is the procedure which I 

 have myself adopted, but not then in agreement with general 

 usage, and in dealing with it it has been necessary to show 

 that the results expressed in this way had a concordance not 

 otherwise demonstrable. I shall not, however, complicate this 

 explanation by too expansive an allusion to this concordance, 

 or to the evident discord maintained by the more usual mode 

 of procedure. The point is this. It is usual to assume that 

 there is a condition known as " rest " which may occupy the 

 whole scene in resting moments, but which also is maintained 

 beneath the phenomena of movement and work. Thus, when 

 the expense of movement is usually presented it is the habit to 

 deduct a certain allowance for the co-existent state of " rest " 

 and all sorts of elaborate estimates are made as to the nature 

 of this allowance, some preferring the degree of expense which 

 is found during " sleep," some that of " sitting/' or of " lying- 

 down." There- is naturally reason behind this quaint method, 

 since it is reasonably advanced that some of the expensive 

 processes of the body have none of that immediate association 

 with work which would make them entirely proportionate to 

 the latter. However, I have abandoned this suggestion and 



