Fui. 22. — Une corner of room C, the main psychological laboratory. 



The fiKure shows the arrangoment of a portion of the apparatus used in taking electrocardiograms under condi- 

 tions of short periods of muscular exertion. The string galvanometer and arc lamp are at the left and not 

 shown in the picture. The subject is connected to the galvanometer by electrode loads, E. A standard- 

 izing resistance arrangement R and a protection resistance R' make possible control of the string's deflec- 

 tions. Electrical condensers C in series with the subject and the galvanometer string minimize its dis- 

 turbance at the moments of physical activity. The photographic camera P is driven bv a motor on the 

 other side of the wall at M . The action of the camera is very quiet, its speed is controlled at S, and the 

 paper or film after exposure is deposited in the large dark box D. The bar B, upon which the subject 

 exercises, is directly above him and within easy reach. 



Fig. 23. — The subject in position during the moments of physical exertion. 



Previous to exertion the subject reclines comfortably in a steamer chair. At a given signal he reaches, grasps 

 the bar above him, and raises himself, thrusting his feet forward to keep all his weight free from other 

 support, and maintains the position shown in the figure until the signal "down," at which he relaxes into 

 the chair. The electrocardiographic record is continuous through rest, exertion, and rest. The experimen- 

 ter occupies a position at the left. 



