1043 



stethoscope willi (lie recording- upparatiis, to coiiimiiiiicale willi tlu' 

 jiir of tlje room through a side opening, so that the impulses were 

 allowed to escape. Gekiiaktz ') points out that, though this conti'i- 

 vance may enfeeble the sound as well as the extraneous impulses, 

 it does not eliminate the latter altogether. In the diiïerent heai't- 

 sound figures he clearly sees indications of the apex-beat. 



Still, considering the extremely beautiful curves taken in Eintho- 

 ven's laboratory, I daresay his method will do for recording heart 

 sounds through (lie chestwall ; not, however, for registering them 

 along the esophagus. It soon became evident that the jerky com- 

 pressions of the rubber-ball could not be excluded from (he curve. 

 For esophageal records the insertion of a stout stilf membrane serves 

 our purpose l)et(ei-. Various glass and mica membranes were tried, 

 but discarded as either -enfeebling the sound or permitting the acci- 

 dental impulses to be recorded along with the heart sounds. Then 



a common phonendoscope on a solid 

 ebonite plate was inserted ; I chose 

 this material because it had proved 

 to transmit heart sounds. The phonen- 

 doscope P, in leaden case {o), was 

 attached hermetically to an afferent 

 tube and had thus been adapted for 

 a circuit with esophagus tube and 

 microphone. If the second aperture 

 was left open, no effect was produced 

 on the recording apparatus either by 

 blowing into the tubes or by squeezing 



^i ■yriihi-Ojokon 



Fig. 1 



tlieni. I( is certain, (herefore, (hat (he ebonite membrane is not 

 thrown into vibration by the impulsive beats of the air. Our greatest 

 obstacle was now overcome. It is true, the sounds were consideral)ly 

 weaker, but what we wanted to hear, was clearly audible. For 

 furthei- i-ecords we used a micro|)hone (in camera plumbica) and a 

 small string galvanometer. This combination had in previous reseaiches 

 proved suitable for recording the low sounds. (P'or the heart sounds 

 Wkisz') and Gkrhaktz determined the number of vibrations at 50— lOOj. 

 At the same time the electrocardiogram was taken in lead II by 

 means of the large string galvanometer, with an arc-ligh( of i(s own. 

 With (he aid of a screen (he cone of eidier lani[) was iiUercepted, 



1) K. Gerhartz. Die Registrierung der Herzschalles. Berlin 1911. 



-) 0. Wkisz. Phono-kardiogramme. Gaupp und Nagel's Sammlung No. 7 Jena 

 1909. 



