DOCKERAY : PHYSICAL FATIGUE AND MENTAL EFFICIENCY. 211 



repetitions was, therefore, twenty-five or thirty, but always 

 the same number for any given individual. The tests of recall 

 were always made the next day, after a definite interval, 

 which was always uniform for a given individual, though for 

 some it was not twenty-four hours. The Hipp chronoscope, 

 prepared for a make-and-break circuit, was connected with 

 the memory apparatus to measure the time between exposure 

 and response. In calculating the per cent of correct responses, 

 all syllables which had formed sensible associations were 

 discarded, except for one subject, R. In his case it was found 

 practically impossible to learn nonsense material when he did 

 not form sensible associations with the syllables. An exami- 

 nation of his records shows that he was fairly constant, when 

 given freedom to associate the material as he chose. I there- 

 fore feel that it is allowable to include his records, though 

 they will deserve separate consideration. After discarding 

 some of the results, as mentioned above, those that remained 

 were used as a basis for determining the per cents. Those 

 responses that had one letter wrong were considered equal 

 to one-half, and those with more than one letter wrong were 

 valued at zero. In a few cases a syllable might be completely 

 reversed. If the first and last consonants were very similar, 

 such responses were evaluated one-half. This occurred in 

 only a very few instances. The average time for the responses 

 was calculated from those responses that were considered 

 wholly or partially correct. 



Two of the subjects, Do. and H., learned the series Sundays 

 at 11 :30 a. m. and tested the next day at 7 :30 a. m. Subjects 

 Br., R. and E. learned at 3 :30 p. m. twice a week, and tested 

 the following days at the same hour. At least one day inter- 

 vened between one test and learning the next series. Part 

 of M.'s work was done at 10 :30 a. m., and an equal amount at 

 4 :30 p. m., but always the period was preceded by an hour of 

 rest from any strenuous work, and an equal number of rest 

 and fatigue days were given at either hour. His tests were 

 twenty-four hours later. The fatigue exercise consisted of 

 long walks of from nine to fifteen miles for Do. and H., 

 twenty minutes in the harness for Br., R. and M., and five-mile 

 runs for E. The results are given in Tables IVa and IV6. 



Throughout all the tests an effort was made to preserve a 

 reasonable regularity in the subject's general condition. By 



3 — Univ. Sc-i. Bull.. Vol. IX, No. 17. 



