314 



Opinions vary strongly as regards the value of the esthesiometric 

 method, but I do uot want to dwell upon that now. 1 have used 

 the method as described by Binet ') and for the sake of brevity 

 I refer to the original description. ^ 



The subjects of the experiment were touched on the back of the 

 hand with the ends of two blunt needles of a certain thickness, 

 which were fixed at various distances froin each other in pieces of 

 cardboard. 



The distances between the needles were (one needle only); 

 1; 1.5; 2; 2.5 and 3 cm. The needles must be placed on the skin 

 simultaneously and always with the same amount of pressure. With 

 such a set of needles the subject is touched in irregulai- order, but 

 with the same distance equally often. These experiments were repeated 

 on five consecutive days at the same time of day. 



Then the percentage of doid)le and single touches was determined 

 for each distance. For the purpose of judging the attentiveness I 

 used as a criterion the fact tiiat a touch with one needle had 

 always to be felt as one point, and with two needles 2.5 or 3 cm. 

 apart always as two points. This has been proved by a prolonged 

 investigation of various normal people. If a mistake is made here 

 it has usually to be considered as a disturbance of the attentiveness. 

 By computing the avei-age number of mistakes it was possible to 

 get an opinion of the attentiveness. It was evidently necessary jiot 

 to reckon witii the bordei- values only, because some patients suf- 

 fering, from dementia and often also those suIFering from Melan- 

 cholia, always answer over all distances with 2 or with 1. In these 

 patients one would come to very misleading results. On the other 

 hand it has been proved, also by investigations of Binet, that it 

 must not always be ascribed to inattentiveness when a touch with 

 one needle is felt doubly. A high degree of attentiveness could 

 sometimes be the cause of this. There is therefore no doubt about 

 it that this method does not always yield trustworthy results, but 

 it is serviceable for measuring larger differences of attentiveness, as 

 are found in pathological cases. 



The second method of investigation consists of the marking tests. 

 It is accurately explained to the person experimented upon what he is 

 expected to do. A large piece of paper, on which there are printed 

 50 lines of groups of dots, is placed before him. These groups, of 

 which there are 25 on each line, consists of three, four, or five dots. 

 The order of the various groups, which are more or less equal in 

 number, is extremely irregular. 



Ö BiNËï. An. ps. XI. 1905. 



