1044 



so that eacli lamp diret-led its light upon one half of the field. 

 Likewise the esophagogmin was sometimes taken simultaneously. 



Fig. 2 (a cardiogram taken from Miss B.) is illustrative of the 

 slia-ht oscillations of the heart sounds. Because we directed all our 

 attention to the heart sounds, no notice was taken of the electro- 

 cardiogram, which accounts for its unsatisfactory record. However, 

 for the present it serves our purpose. At /y we observe most distinctly 

 a constant, rather slow vibration of the string, lühicli occurs before 

 the systolic portion of the electrocardiogram and is, therefore, of 

 auricular origin. (In the experiments, advisedly arranged, the recording 

 apparatus exhibited only a scarcely measurable slowing). Here then 

 we managed to record part of what is perceived by the ear. It 

 does not amount to much; the second auricular sound is wanting, 

 but the recording apparatus, on which moreover only weakened 

 sounds are directed, will ever be inferior to our highly sensitive 

 ear. It follows, that from these curves we cannot identify the real 

 commencement and the real termination of the heart sounds, the 

 initial and the terminal vibrations not having been well represented 

 in the tracing. 



Of the tirst auricular sound only the loudest portion has been 

 traced. The ventricular sounds, which are much louder, yield much 

 better tracings and conti rm Einthoven's experiejice with regard to 

 the form of the heart sounds. They also point to his method being 

 perfectly reliable for the sounds through the chestwall, since we 

 gather from them that the first auricular sound is made up of three 

 phases (a slo\v initial vibration, then the rapid main vibrations and 

 finally a slower terminal oscillation), whereas the second sound 

 consists of rapid vibrations only. We found the period of vibration 

 of the first auricular sound to be rather low, viz. 50 per second. 

 Further particulars are shown in Fig. 3, taken from subject t. D. ; 

 however, here also the amplitudes are small, owing to considerable 

 damping. First of all we observe in one heart-rhythm three well- 

 defined groups of large vibrations. I and II represent the ordinary 

 ventricular sounds and commence at the familiar spots, viz. some- 

 where about /S and at the end of T. The vibrations preceding I 

 start at a point some way from the foot Q of the /^-peak, and must, 

 of course, be of ventricular origin. I marked them Iv. A couple of 

 slight vibrations at .Y indicate the real commencement. It will be 

 seen that the first sound like the first ventricular sounds is made 

 lip of ditferent parts, with differing vibration frequency. At the end 

 of the first ventricular sound we observe a couple of unlooked-for 

 slo\v vibrations (Ilr) with the shortest possible gap between them. 



