x86 The Newly -Discovered Force. [April, 
the apparatus was most thoroughly insulated. As galvano- 
scopic frogs are susceptible to mechanical irritation, it was 
suggested that possibly the vibrations, from the apparatus 
communicated through the wire, caused the contractions, 
and on using the key (Fig. 2) instead of the self-vibrator 
the force caused no contractions. Returning to the self- 
vibrator (Fig. 1) contractions appeared. When the wire 
connecting the apparatus with the frog was shortened, the 
contractions increased in vigour. That the frog was suscep- 
tible to vibrations was shown by striking a very large tuning- 
fork and touching it to the sciatic nerve, and sometimes 
contractions appeared when the vibrating fork did not touch 
the nerve, but was held at a distance of J or f of an inch 
from it. It was shown, however, by experiments on pith 
balls, that electricity is generated by a vibrating tuning-fork, 
and this electricity — which is probably the result of the im- 
pact of the steel against the air — may possibly have caused 
the contractions in the frog. On testing this frog by the 
galvanic current it was found that one eleCtro-poion cell, 
after going through a resistance of over 1,000,000 ohms, or 
about 75,000 miles of telegraph wire, easily caused con- 
traction. 
In later experiments, however, made with Prof. Smith, I 
failed to cause any movement of the frog by mechanical 
vibrations alone, even when the nerve was held close to the 
self-vibrator ; but when the force was allowed to pass through 
the nerve and muscles of the frog it contracted. When the 
key was used instead of the self-vibrator the frog did not 
move, even on the opening of the circuit. When the force 
coming from the self-vibrator was passed through several 
inches of water, so as to eliminate the error of mechanical 
vibrations, the muscles of the frog contracted. It is pro- 
bable, therefore, that when developed rapidly and in large 
amount, as in the self-vibrator, this force causes contraction 
in the galvanoscopic frog. 
The presence of electricity, in its different forms, is deter- 
mined by the electroscope, the Leyden jar, the galvanometer, 
the electrometer ; electrolysis, or eleCtro-chemical decom- 
position, by physiological effects, and by light, heat, or 
ozone produced. This force, as thus far studied, does not 
defleCt the leaves of the electroscope, nor charge the Leyden 
jar, nor move the needle of Thomson’s delicate reflecting 
galvanometer or electrometer, nor decompose iodide of po- 
tassium, nor produce any demonstrable physiological effects 
on the nerves of motion or sensation, or speech, or on the 
muscles or other tissues ; nor does it under all conditions 
