ELECTRICAL PHENOMENA AND METABOLISM OF ARUM SPADICES. 317 
or by more prolonged continuous heat the warmed spot was rendered 
“zincative ’ (galvanometrically negative). Thus the electrical effect 
of little heat—z.e., of a comparatively small rise of temperature—is of 
the opposite sign to that of much heat—i.e., of a comparatively large 
rise of temperature, and to that of injury; and we think there can be 
no doubt that the effect of much heat is in reality an effect of local 
injury, which, as is well known, is of the same electrical sign (zincative 
or negative) as that of the effect of local excitation. We note, there- 
fore, as our conclusion that the first electrical effect of local heat is of 
heat 
heat 
heat 
heat 
Effect of heat locally applied as described in the text under B (six times repeated) 
and under A (four times). In the first group B is rendered anti-zincative. In 
the second group A is rendered anti-zincative. 
opposite direction to that of local excitation—.e., that the effect of 
moderate heat is anti-excitatory. 
Similar experiments upon isolated frog’s nerve gave similar results, 
from which we draw a similar conclusion confirmatory of the idea that 
the effect of moderate heat is anti-excitatory. : 
Similar experiments upon isolated frog’s skin were particularly 
satisfactory. In this case the electrical effect of local excitation was 
to render the excited spot ‘ anti-zincative ’ (galvanometrically positive), 
and that of local moderate warmth was to render the warmed spot 
“zincative ’ (galvanometrically negative). Thus, whereas the. effects 
of excitation and of heat are of reversed sign upon the skin as compared 
with muscle and nerve, the electrical effect of local heat is, as in 
the case of muscle and nerve, of opposite direction to that of local 
