1902.] 



On Skin Currents, 



391 



Exc. by break 

 10,000 +. 

 1st day + 0-0180 volt 

 2nd „ + 0-0050 „ 

 3rd „ — 

 4th „ + 0-0020 „ 

 5th „ — 

 6th „ — 

 7th „ 



Exc. by break 



10,000 

 + 0230 volt 

 + 0-0175 „ 



+ 0-0030 „ 



0-0040 



+ 0-0047 „ (skin of nipple, 

 fig. 5) 



8th „ - 0*0005 „ + 0-0005 „ (ordinary skin, 



polarisation only). 



In all cases where note -was taken of the " normal current " this was found to 

 be of ingoing direction, i.e., contrary to what might be given as current of injury 

 from inner to outer surface. The voltage was in no case nearly as high as th©' 

 voltage of a response — e.g., the following are values taken almost at random from my 

 laboratory note-book : — 



Skin No. 



(nipple). 



In the second group of cases, Nos. XII to XVIII, the skins were those of infants 

 on whom circumcision had been performed, and included therefore a layer of 

 mucous membrane. In these cases also the normal current as regards the layer of 

 true skin was ingoing] and the response was outgoing. But the results are com- 

 plicated by reason of the mucosa, which as far as I have yet seen responds usually 

 by an ingoing current. Further observations directed to this point are, however,, 

 necessary. 



The conductivity and its modifications are in all cases indicated by means of 

 standard deflections by a given voltage — usually 0-01 volt. The resistance, in a few 

 instances wheatstoned, is generally calculated by reference of the deflection to that 

 of the same voltage through a megohm — and usually the disposition of the gal- 

 vanometer was such that 0*01 volt through 1 meghom {i.e. l'lO -8 amp.) gave a 

 deflection of 10 mm. The values for conductivity are given in millimetres of 

 deflection by 0*01 volt, and each millimetre expresses therefore 1*10- 9 mho. 



I 



1st day 



-0-0027 volt. 



II 



1st „ 



-o-oioo „ 



3» 



2nd „ 



-0-0044 „ 



■ » 



3rd „ 



-0-0050 „ 



33 



4th „ 



-0-0040 „ 



33 



7th „ 



-0-0037 „ 



III 



2nd „ 



-0-0040 „ 



J3 



3rd „ 



-0-0060 „ 



IY 



1st „ 



-0-0130 „ 



