ANIMAL ELECTRICITY. — LECTURE V. 



I I 



isinof current, which is to be at the constant value 

 of about I "5 volt ; we shall lead off the extrapolar 

 current by 6 and 5, then by 5 and 4, then by 4 and 3, 

 that is to say, with distances between leading-in and 

 leadino--out electrodes at 3, 2 and i centimetres. 



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We begin with e e' at 6 and 5, and complete 

 the polarising- current through i and 2 ; the electro- 

 tonic deflection is just visible to you, being about 

 5 cm. of scale. We make a second trial with e e/ at 

 5 and 4 ; the electrotonlc deflection is larger, about 

 30 cm. of scale. We make a third trial with e e' at 4 

 and 3, the electrotonic deflection is much larger still, 

 right off scale, and to get a measurement of this deflec- 

 tion the galvanometer would have to be shunted. 



From these data, and still more clearly from this 

 table, we see that the magnitude of an electrotonic 



Distance between leading-in electrodes = i cm. 

 Distance between leading-out electrodes = i cm. 

 Polarising current by i leclanche cell (= i"4 to 1*5 volt). 



current diminishes very rapidly with increasing dis- 

 tance between leading-in and leading-out electrodes. 



