This is an original work of art by Norman Gitzen. You may use this image free of charge to enhance your presentations or student handouts.  Click on image, or, for best image quality,  right click and SAVE image.  For permission and charges for use in publications or for marketing uses, or to see more of his beautiful art, please contact the artist at his website: www.normangitzen.com.

This photograph is courtesy of Kathy Singer.

Original illustration by Dawn Altman.  

This photo has been in the public domain for some time.  It is NOT Dr. Einthoven.  Notice the vats of saline solution being used as electrodes