Validity of Ergo graph as Measurer of Work Capacity 35 



where it is necessary to suspend exercise for any length of time 

 caution must be taken against making the time too long lest the 

 records taken afterwards be affected by the loss of inurement, 

 which comes rapidly and is most potent in influencing the height 

 of the records after the first two or three have been taken. A 

 few records taken upon unpracticed subjects, for instance, both 

 before or after some influence which is thought to affect muscu- 

 lar power, are therefore without the slightest claims whatever to 

 trustworthiness. The ergograph is quite unadapted to obtaining 

 statistics upon a large number of individuals, except they be of 

 the most general character. It may be used for obtaining accu- 

 rate results only upon individuals studied under the most exact- 

 ing conditions and for long periods of time. The work is ex- 

 hausting and therefore tends to create an unfavorable disposition 

 towards the experiment itself. This, however, will depend very 

 much upon the number of records a day. Our experiment seems 

 to indicate that not more than two records a day for each hand 

 should be taken. When two records a day were taken the great- 

 est practice gains were made, although in the earlier. part of the 

 experiment, before the reagent had become thoroughly habitu- 

 ated and skilled, that seemed a pretty heavy task. 



The conditions under which practice gain is greatest. — The 

 influence which the rest periods have exercised upon the growth 

 of practice has already been touched upon, but a more detailed 

 study of the effects from a suspension of practice for a period 

 yields certain interesting results. In the following table we have 

 brought together the average daily performances for the last four 

 days before each rest period and for the first four days after 

 each rest period. The number four is more or less arbitrarily 

 chosen. The effects of incomplete inurement are usually shown 

 within two days, and after that they begin to disappear. 



"3 



