I'AROXVSMAL tRRfeGtJLARltY O^ TttE HEART 1^ 



whatever on the movement of the auricles, while the ventricle is rendered 

 slower and more regular or may be arrested completely. Philips believes 

 that the fibrillation of the auricle is lessened by vagus stimulation. (It 

 may be mentioned that the tremor in the tracing of the auricle during 

 delirium often appears less marked under vagus stimulation, but this is 

 due to the fact that the ventricle is slower and communicates less 

 movement to the auricle ; the fibrillation of the auricle causes no 

 movement of the lever in itself) The more regular contraction of the 

 ventricle under vagus stimulation is obviously due to the fact that the 

 impulses from the auricle pass less readily through the block ; when they 

 are altogether excluded by section of the auriculo-ventricular band, the 

 ventricle beats regularly (Fredericq.) The pulse was recorded by Philips 

 as well as the movements of the ventricle and auricle, and during the 

 auricular fibrillation it is accelerated and very irregular, as we have also 

 observed in our experiments. See Figs. 5, 6. 



Fig. 5.— Tracings (Hurthle's tonometer) from the carotid of a dog. The lower tracing is 

 the normal ; the upper one was taken during auricular fibrillation from rapid electrical stimula- 

 tion of the auricle. 



Stimulation of the dog's auricle with rapid induced shocks causes 

 fibrillary contractions, which pass off when the current is shut off, or very 

 soon afterwards. On repetition several times the interval between the 

 cessation of stimulation, and the return of the normal auricular contrac- 

 tions, becomes longer, until finally it may continue for an hour or more 

 after the electrodes have been removed. Such cardiac depressants as 

 chloroform have no remedial effect, even when pushed until the ventricle 

 almost ceases under them. The only way in which we have been able to 



(107) 



