Applications of Electronics in Medicine 41 



by Hollmann and HoUmann,-^ Wilson and Johnston,^"* and 

 others. 



HoflF, Kramer, DuBois and Patten -^ have employed valve- 

 amplifier technique for recording the electrocardiogram of the 

 embryonic heart of the developing chick. Mann and Bernstein ,-^- 

 Ward and Kennedy "'^ and others have used electroencephalo- 

 graphic technique for the registration of the electrical variations 

 of the human foetal heart. 



The Phoiioelectrocardioscope 



The phonoelectrocardioscope ^^' ^-' ^'^' ^-^ incorporates a double- 

 beam cathode-ray oscilloscope fitted with a long afterglow screen, 

 which permits the simultaneous and constant, viewing of a pair 

 of phenomena such as the phonocardiogram and electrocardio- 

 gram at the patient's bedside, while the heart sounds can be 

 heard at the same time through an electrical amplifying stetho- 

 scope or a loud-speaker. The double-beam cathode-ray oscillo- 

 scope has also many uses in biology and medicine.^ ^ 



1^ ^tv^ VT'". 



FIG. 1. The Phonoelectrocardioscope. 



