CONNECTED WITH THE BEAT OF THE MAMMALIAN HEART. 179 
Apex to 
Hg. 
and Base to 
H,SO,. 
Variation N. 
Apex to 
1 > 
,, Mouth to 
99 
,» 9 
N. 
Base to 
?; 
,, Mouth to 
9 9 
9 9 
NS. 
Apex to 
? 9 
,, Mouth to 
9 9 
9 9 
N. 
Base to 
5 9 
,, Mouth to 
99 
9 9 
NS. 
Mid ventricle to 
9 9 
,, Mouth to 
99 
99 
NS. 
Apex to 
9 9 
,, Base to 
99 
9 * 
N. 
Mid ventricle to 
99 
,. Base to 
99 
9 9 
NS. 
Apex to 
9 9 
,, Base to 
99 
99 
N. 
Apex to 
9 9 
,, Mid ventricle to ,, 
9 9 
N. 
Here again it appears very plainly that a lead-off from the mouth is equivalent to 
a lead-off from the base of the heart. 
Complementary experiment .—In order to obtain some idea of the distribution of 
potential in surrounding parts when different portions of the heart are at different 
potentials, I took observations with the capillary electrometer, leading off from various 
parts of the body, and leading in the current of a Daniell cell by pins transfixing 
the heart at base and apex {vide fig. 4). The observations were taken on a nim als the 
day after death, left exactly in the position in which their hearts had been examined 
on the previous day. 
Experiment 7.— Cat. April 17, 1888. Twenty-four hours after death. Heart 
transfixed at apex and base by pins constituting the electrodes of a Daniell cell. 
Direction of current as in diagram above, e and ^ are the leading-off electrodes to 
mercury and sulphuric acid. The Daniell circuit is made and broken by a spring key, 
and the consequent variations of the electrometer observed when e and i are applied 
to various parts of the body. The results are as follows : — 
2 A 2 
