PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM [1HB5. 



EXPLANATION OF PLATE I. 



Fig. I represents the tracings taken while the heart was working under the in- 

 tiuence of atropized blood. 



Fig. II shows tracings obtained while the heart was under the influence of normal 

 mitrieut blood-mixture; it is also intended to illustrate the promptness and complete- 

 ness with which the heart passed out from under the influence of atropia, as can be 

 seen on the left-hand aide of the figure, where part of the tracing taken under atro- 

 l)ized blood is left on for the purpose of showing this. 



The cumulative effect of this drug, therefore, seems almost insignificant enough to 

 bo entirely disregarded, so far, at least, as the heart is concerned. 



