On. tlic Relation of Muscle Sense to Pressure .Sense 5 



Observations were taken upon two experienced reagents who 

 knew the apparatus and its mode of operation and upon thirteen 

 naive students who were quite unaware of what was expected of 

 them. They were required only to say whether the two weights 

 presented in close succession were the "same" or whether the 

 second was "heavier" than the first. The answers of the experi- 

 enced reagents might be "same," "doubtfully same." "doubtfully 

 heavier," and "heavier." In practice the doubtful judgments 

 were very few, and it will be seen that they have been of no par- 

 ticular significance for the results. The results are presented as 

 so many series. A series consists' of the judgments upon six pairs 

 of stimulus magnitudes taken either in the ascending direction 

 from the standard to the heaviest weight or in the reverse order 

 from the heaviest to the standard. From four to eight series, 

 usually four series, were taken at a sitting, and the experiments 

 were made four or five times a week for more than two months. 

 As our purpose did not include an accurate determination of the 

 threshold or a study of the various influences that might affect 

 the run of the judgments themselves, we have thought it worth 

 while to conduct the experiments without view to eliminating 

 the effects of space and time location which have been so care- 

 fully examined by Miiller^ and Schuman and Martin and Miil- 

 ler. As a matter of fact, the apparatus eliminates the errors that 

 might arise from differences in space location, since the arm al- 

 ways occupies the same position and the weights are brought to 

 it. Our purpose was rather to find a threshold by a given method 

 and then to study the effects of muscular contractions upon the 

 threshold determined by the same method. 



The first set of experiments will be known as passive palm 

 pressure. The second set of experiments was instituted shortly 

 after the first began, and from that time forth sittings under the 

 second were made to alternate with sittings under the first set. In 

 this set the support back of the hand was slid back and the hand 

 allowed freedom to react against the pressing cork. When the cork 

 was brousfht into contact with the hand the reagent was required 



^Loc. cit. 



179 



