112 'Journal of Comparative Neurology and Psychology. 



approximately twice as strong as the other, in reality one division 

 on instrument A equaled 0.6 division on instrument B. The in- 

 strument A enabled me to stimulate with tensions from to 2000 

 me"., while instrument B enabled me to stimulate with tensions 

 from to 4000 mg. Each instrument was divided into arbitrary 

 divisions, circular degrees, and since I was dealing with relative 

 differences I did not translate the figures into terms of tension. All 

 the figures that are included in the following tables are, however, 

 directly comparable.'^ 



Fig. 2. — Esthesionieter of Blocb. Tbe figure is about one-tbird tbe size of 

 tbe instrument. 



The j)resence or absence of pressure sensations was determined 

 by stimulating the parts with the pointed, l>ut not sharp, end of a 

 pencil. On normal parts this stimulus was immediately appreciated. 

 Pain from pressure was determined by an algometer. The surface 



'Tbe value of such an instrument for determining differences in toucb 

 sensations was well brougbt out in some experiments, not yet publisbed, on 

 the touch thresholds in different parts of the body. One subject whom I 

 examined carefully showed an increase in threshold values in tbe lower leg 

 and foot on tbe left, although no similar difference was foiuid to exist in 

 other parts of tbe body. This leg was also smaller than tbe right, in circum- 

 ference. When asked to explain the latter dift'erence tbe subject replied that 

 both knee and ankle of this leg bad been injured at two different times and 

 that for a period of six months six years previously she bad this leg bound up 

 and almost immovable. Another subject, a case of traumatic epilepsy, showed 

 an increase in threshold values for touch on tbe right upper arm and shoulder, 

 on tbe back over the scapula and over tbe chest above tbe breast, although 

 otherwise both sides were the same. This was tbe only sensory or motor 

 change that I found in this woman, and this persisted after tbe operation 

 that was undertaken for her relief. In neither case did tbe testing widi cotton 

 show the least difference between tbe two corresponding segments of tbe body. 



