Page:Collected Physical Papers.djvu/294

drops of diluted solution of sodium carbonate and you observe the growing exaltation of the response. (fig. 69).

I now pass on to the effect of poisons. Any of the substances already enumerated may be used as the

Fig. 69. Stimulating action of Na₃CO₃ on tin.

toxic agent. After obtaining the normal response I apply a poisonous solution of oxalic acid. The electric response is now completely killed and all our efforts, by intense stimulation to reawaken them, fail (fig. 70).

Fig 70. Abolition of Response by Oxalic acid.