VI.] 



OUTGOING EFFECTS 



103 



It is an easy matter in the case of an animal like the cat, 

 to test the skin in situ. Two or three hours after death, when 

 the muscles are no longer inconveniently excitable, a pad is 

 cut off, and one electrode is applied to the wounded surface ; 

 the other electrode is applied to an intact pad. The accidental 



oo 



' FlG. 42. (4219.) Outgoing responses of the pad of a cat's foot, directly excited 

 by single break induction shocks in both directions, and by tetanising currents in 

 both pairs of directions. 



current (which is not an " injury current," since its direction in the 

 cat is from intact to injured spot, but the normal and accidental 

 ingoing current at the uninjured spot) is compensated, and the 

 blaze test applied in the usual way. Both responses are in 

 the same direction as that of the accidental current, from intact 

 to wounded spot, ingoing through the intact skin. These 

 are evidently not negative variations of any injury current. 



We may provisionally infer from the absence of obvious 

 injury current that the subcutaneous connective tissue is of 

 very inert character, and that an unpolarisable electrode 



