RESPONSE OF ANIMAL AND VEGETAL SKINS 31 1 



For the following experiments, I took the skin of gecko, 

 which can be detached from the body with very little injury. 

 This animal offers remarkable facilities for many electro- 

 physiological experiments. Its isolated tissues can be main- 

 tained in a living condition for a very long time. Its sciatic 

 nerve affords us a specimen about 15 cm. in length. Thus 

 for electro-physiological investigation, it provides much 

 greater advantages than the frog. 



FIG. 191. Photographic Record of Abnormal Diphasic Responses in Skin 

 of Gecko, converted to Normal, after Tetanisation 



Taking a specimen of gecko skin, which was in a favour- 

 able tonic condition, I obtained the series of normal responses 

 to equi-alternating shocks, which is given in fig. 190. The 

 responsive current here flowed from the inner to the outer 

 surface. I next took another specimen, which was in a less 

 favourable tonic condition, and obtained records of its 

 responses, here seen (fig. 191) to be diphasic. An intervening 

 period of tetanisation is seen, however, to restore the normal 

 response. 



