]70 
DR. A. D. WALLER OX THE ELECTROMOTIVE CHANGES 
of these irregularities. Most of the observations reported in Part I. had for their 
object to clear this ]3art of the subject as far as possible to me. 
§ 2. Experimental Modification of the Electrical Variation connected ivitfi the 
Spontaneoim Beat. 
The methods followed have been in the main those described in the paper already 
referred to,”" wdth certain modifications of detail, such as the use of d’Arsonval’s 
chloride of silver electrodes (which proved to be convenient and excellent for the 
purpose in view), and with this difference, that, in order to examine the as far as 
possible intact and uninjured organ, the heart was examined in situ, the thorax being 
laid open and its walls fixed to a board immediately after the decapitation of the 
animal. The heart, liaving been examined in situ, was then excised and re-examined 
electrically. 
Experimeni 1 .—Kittens heart. March 31st, 1888. 
Time after 
A to Hg. 
A to H.SO,,. 
death. 
min. 
var. 
Spontaneous beat . 
5 
SN 
Excited beat (exc. of apex). 
Spontaneous beat after injury of base. 
10 
SN 
S 
Heart excised— 
s 
Excited beat (exc. of base). 
NS 
„ (exc. of apex). 
SN 
Spontaiieous beat. 
20 
SN 
„ after iujuiy of apex. 
N 
When electrode B was in contact with the auricle, which was heating twice to each ventriciilar beat, 
the variation was of the folloAviirg rhythm:— 
n wSN n «SN n ??.SN, 
or, expressed graphically. 
When electrode B w^as in contact wdth the base of the ventricle the variation w'as of the rhythm 
SN . . . SN, the electrometer not being inflirenced by the auricular contractions. 
* Loc. cit., p. 235 (heart led-off to electrometer from tw'O points A and B), 
With 
Wilh 
A to HgSO.j'l variation N signifies A negative to B. 
B to Ilg J „ S „ B „ A. 
A to Hg 1 „ N „ B „ A. 
BtoH.SOJ „ S „ A ,, B. 
