Applied Biophysics 



FIG. 3. The same apical phonocardiogram has been recorded by both beams on 

 moving film. It will be noted that they are apparently 180° out of phase, and that 

 there is no "fogging." Illustrative tracing taken with the author's phonoelectro- 

 cardioscope. 



reversing the input leads for the bottom trace. The pair of 

 traces have been recorded on moving fihn, and, despite the 

 long afterglow screen, there is no trace of "fogging." Figure 

 4 shows a logarithmic phonocardiogram and electrocardiogram, 



FIG. 4. Logarithmic apical phonocardiogram. Electrocardiogram, lead II. Re- 

 corded on moving film. Illustrative tracing taken with the author's phonoelectro- 

 cardioscope. 



lead II, recorded on moving film. The precaution mentioned 

 above has been adopted, and the electrocardiogram shows the 

 right way up. 



Figure 5 shows how a pair of traces look on the screen when 

 viewed directly. The top trace is electrocardiogram, lead II, 

 and the bottom trace is the jugular-pulse sphygmogram. They 

 have been photographed by focusing a camera on the fluorescent 

 screen of the double-beam cathode-ray oscilloscope, and taking 

 one traverse of the pair of spots as they appear for visual ob- 



