Dr. Alfred P. Southwick a dentist from Buffalo thought that the electricity may be used in the medical practice as a anesthetizing mean.
Once the dentist witnessed an intoxicated man touch a live electric wires and died immediately.
Given that the man died so quickly, Dr. Southwick concluded that electricity could be used as an alternative to hanging for executions, as the convict died quickly and with less torment.
Source: Iravaban.net