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DR. A. D. WALLER AND MR. E. W. REID ON THE 
ties clue to an excessive susceptibility to local injury; of such susceptibility we had 
abundant evidence ; the delirium, which is so apt to supervene, is its extreme instance. 
We see no escape from the conclusion that the Mammalian ventricle is an organ 
not only controlled by nerves, but also co-ordinated as to the action of its several parts 
through intra-muscular nervous channels. A monophasic variation can consist only 
with simultaneity of action throughout the organ, or with the successive action of its 
several parts so rapid as not to be revealed by either galvanometer or electrometer, or 
with action confined to one part of it, or with action predominant at one part; it is 
not consistent with the comparatively slow successive action of various parts of the 
Photograph 7. 
Variations accompanying spontaneous beats of Pappy’s heart. The variations of the auricle are 
visible as small black teeth on the tracing, and it may further be seen that the variations of 
the ventricle are in two instances monophasic, indicating negativity of apex, and in three 
instances diphasic, with first phase = apex negative to base, second phase = base negative to apex. 
(Apex to Hg. Variation of auricle S ; of ventricle N and NS.) 
ventricle by muscular transmission. Such simultaneity or approximate simultaneity 
can, we think, only be effected by nervous channels, and that conduction by nervous 
channels plays a part in the simultaneous and co-ordinated action constituting a beat 
is supported by other considerations, by measurements of the rate of conduction, for 
instance, such as we have given above, and still more strongly, we think, by the 
electrometer sequence repeatedly observed by us when the heart is dying and its 
parts becoming evidently asynchronous in their action, viz., negativity of auricle, 
followed by negativity of apex, followed by negativity of base. This can consist 
only with the existence of nervous channels along which excitatory impulses have 
passed from auricle to the apex. (Photo. 7.) 
Usually it is not till several minutes have elapsed after excision that the diphasic 
variation is seen. It doubtless depends on the fact that with the slowness of action 
asynchronism of acting parts becomes manifest, but whether we have to do with a 
