180 
DR. A. D. WALLER ON THE ELECTROMOTIVE CHANGES 
w 
fe near A tbe variation was S, that is, — 
nth i 
S, „ 
with 
wnth 
with 
with 
'■ i near B 
e near A 
i in mouth 
e to leg 
i in mouth 
e near B 
i in mouth 
e near B 
i at leg 
S. 
N, 
N, 
+ / 
+ 
These variations were precisely such as might have been anticipated from theoretical 
considerations ; they were reversed wuth reversal of the Daniell current; they are 
confirmatory of the supposition above made that a lead-off from the mouth is 
equivalent to a lead-off from the base, and that a lead-off from the lower extremity 
is equivalent to a lead-off from the apex. Experiments of a similar character with 
single induction shocks gave precisely similar results. 
Experimeyit 8.— Kitten. April 21st, 1888. Death by chloroform. 
1. Mid ventricle to Hg. 
2. Mid ventricle to Hg. 
3. Leg to Hg. 
4. Auricle to Hfr. 
o 
Mouth to H3SO4. 
Leg to H3SO4. 
Mouth to H3SO4. 
Leg to H3SO4. 
Variation 728. 
778. 
sN. 
5 and or 5778. 
This experiment presents several points of interest. The third observation is the 
first which I have made upon an animal leading off the heart from two remote points, 
viz., leg and mouth. The variations with each contraction of the heart were small, 
but unmistakable. (It should be remarked that the chest was open and that circu¬ 
lation had ceased, the animal having been dead about ten minutes.) The variation 
Avas such as to indicate— 
1st phase. Negativity at leg. 
2nd phase. Negativity at mouth. 
As will presently be shown, we have reason to admit the leg as indicator of the apex 
potential, the mouth as indicator of the base potential. Thus we have in this case— 
1st phase. Negativity of apex. 
2nd phase. Negativity of base. 
In the fourth observation the auricles Avere contracti 112: tAvice to each A^entricular 
contraction ; AA'hen the auricle contracted the variation was s, indicating negati\’ity of 
