188 
DR. A. D. WALLER OR THE ELECTROMOTIVE CHARGES 
and the unfavourable combinations :— 
Mouth and left hand ; 
Right hand and right foot; 
Right hand and left foot. 
The above results are diametrically opposed to those obtained on the normal sub¬ 
ject. Those obtained with the combinations indicated below were identical'"' in the 
two cases, favourable combinations in both being ;— 
Mouth and right foot; 
Mouth and left foot; 
Left hand and right hand ;* 
while in both we find the unfavourable combination :— 
Left foot and right foot. 
Detailed comment is needless; the complete harmony of the facts stated will be 
clearly recognised in the tabular summary on p. 191 ^vith the assistance of the appro¬ 
priate diagrams (figs. 6, 7, 8). 
In each instance of the entire series a favourable combination is formed when the 
electrometer is connected loith two heteronymous points a and b, while am unfavourable 
combination is formed when the connection is made with two homonymous points 
a, a or b, b. 
The above observations supply abundant proof that in the contraction of the heart 
there is a time during which the apex and the base are not iso-electric. 
From our knowledge of the diphasic variation of the hearts of Animals, we are 
further assured that on Man the inequality shall be of a double character; the part 
which first becomes negative is also the part which first ceases to be negative, the 
part which last becomes negative is also the part which last ceases to be negative, so 
that a diphasic change will occur in consequence of— 
1. Unbalanced negativity where action commences. 
2. Unbalanced negativity where action lasts longest. 
What are the character and direction of the electrical changes observed on Man 
with the beat of the heart ? 
In answer to this question, I shall select the most favourable cases for examination, 
i.e., those in which the variation has presented itself in a well-marked and readable 
form. I have followed two channels of information, each presenting special advantages 
and disadvantages. Simple inspection of the capillary under a ^ objective is the 
ready and convenient means of investigating a series of combinations. Photography 
of the oscillating column of mercury with simultaneous photography of cardiac move- 
* The direction of the variation with the two hands is opposite in the two cases, as wall presently be 
noticed. 
