Electromotive Phenom. of the Mammal. Haert. 



275 



negativity of the uninjured points and lasts during the whole period 

 of contraction of that point. As an example of a „stepped" curve 

 we give fig. 22, Plate XVI which can be explained as below, Figs. 7 

 and 8. 



It is perhaps necessary to 

 meet a possible objection to 

 our interpretation of some of 

 the curves. It might be said 

 that in the triphasic curves we 

 have mistaken negativity of the 

 auricle for negativity of the 

 base of the ventricle. To meet this objection, we have taken photo- 

 gi'aphs of the heart variation, leading off at one time apex and auricle 



m 



Fig. 8. 



4' 

 f 



and at another time base and apex, and could detect no difference 

 between them; in fact, with our electrometer the electrical change of 

 the auricle was too small to produce any movement of the meniscus. 



General summary of results. 



1. Our experiments show that in general, the conclusions of 

 Sanderson and Page with respect to the heart of the cold-blooded verte- 

 brate, can be applied also to that of the mammal. 



2. The ventricular contraction is a single wave, .starting from 



18* 



