172 
DR. A. D. WALLER OR THE ELECTROMOTIVE CHANGES 
The early inoiiopliasic variation which Dr. Keid and I had so frequently under 
observation Avith the Mammalian heart immediately after excision was probably of 
this nature ; it is, indeed, “ the expression of local predominance of a change taking- 
place throughout the whole ventricle,” * but our opinion concerning it, to the effect 
that the single variation is proof of a practically single and simultoneous change 
Eig. 1. 
Apex negativity, followed by 
base negativity 
Enbalanced negativity of base 
Unbalanced negativity of apex 
Apex negativity, followed by 
base negativity 
Base negativity, followed by 
apex negativity 
(Apex of beai't to mercury of electrometei'. Base of licait to sulplmric acid of electrometer.) 
taking place throughout the ventricle, is no longer justified. The diphasic variation 
can be, as above described, rendered monophasic by injury on the Mainmalian, as on 
the Batrachian, heart; bearing in mind the extreme susceptibility of the Mammalian 
heart, we must regard as highly probable that a monophasic variation is a conse¬ 
quence of injury, and that the normal variation is diphasic. 
Conjirmafory experiment .—That a monophasic variation is no evidence of simul- 
* Log. cit., p. 241. 
Xature of beat. 
1. Normal spontaneous 
2. Spontaneous Avitb injured 
apex 
3. Spontaneous witb iujui-ed 
base 
4. Excited from apex . 
5. Excited from base 
Electrical variation. 
Tff 
SN 
N 
SN 
NS 
