Page:Collected Physical Papers.djvu/302

282 are obtained with the clamp at the approximate balancing point:

Effect of Chemical Reagents.—It will be shown that keeping the electrolyte by which contact is made constant, the electric excitability of the wire depends on the molecular condition of the wire. Certain electrolytes, such as dilute solution of NaCl, dilute solution of bichromate of potash and others, are normal in their action, that is to say, with such contacts the response to stimulation is practically the same as with distilled water contact.

Contact made with dilute NaCl solution may therefore be regarded as the normal contact. There are again certain chemical reagents which enhance the electrical excitability; others on the contrary produce great depression, or abolition of excitability.

We may compare the relative electric excitability conferred by chemical reagents by the method of balance. Having previously obtained a balance (with water or