70 ON DIGITALIS, WITH SOME OBSERVATIONS ON THE URINE. 



this resistance is much increased, and the heart stops in 

 diastole. 



The series of experiments on which Traube founded his views 

 were as follows : — He injected infusion of digitalis of such a 

 strength that one syringe-ful was equal to the extract of 8 

 grains of digitalis leaves, into the veins of dogs, and found that 

 while salt and water produced no effect on the pulse, and one 

 syringe-ful of infusion raised it from 128 to 132, four syringe- 

 fuls brought it down to 32 ; while after a fifth it suddenly 

 rose to 160, and in 10 minutes more to 174. In another, with 

 a pulse of 108, it was reduced by 2^ syringe-fuls to 33, but 

 with f of a syringe-ful more it rose to 202. Several other 

 experiments gave an exactly similar result. To find whether 

 the action was through the vagus or not, he made seven more 

 experiments. In one, for example, after reducing the pulse 

 from 121 to 48, the right vagus was cut, and in two minutes, 

 when again counted, the pulse was 66. On dividing the left 

 vagus it then rose to 204. The same result was obtained by 

 dividing both vagi at the same time. After dividing both vagi,, 

 the slowing of the pulse after the injection of digitalis was 

 hardly observable. From these experiments Traube concluded 

 that digitalis operated through the regulating system only. 

 This theory was very generally adopted for some time, but 

 Winogradoff, finding from experiments with the hoemadynamo- 

 meter, that when the instrument was inserted into an artery, 

 and the vagi stimulated so as to cause slowness of the pulsa- 

 tions, the arterial tension immediately fell ; while, when the 

 slowing was produced by the injection of digitalis, there was 

 neither increase nor diminution of the tension, concluded that 

 Traube's view was erroneous, and totally denied that the slow- 

 ing of the pulse, produced by digitalis, was through stimulation 

 of the vagi or medulla oblongata. Traube being thus induced 

 to re -consider his theory, made some experiments by injecting a 

 weak solution of woorari into the veins of a dog, and keeping 

 up artificial respiration to obviate the disturbing influence 

 which the rise in tension consequent on division of the vagi 

 would have caused, and then injecting infusion of digitalis, he 

 found that the tension rose in one instance from 159 to 260 



