PREFATORY NOTE 
THE method of measuring induction shocks described 
in the following pages was developed in a series of papers 
published between 1908 and 1911 in the American Jour- 
nal of Physiology. Extended use of the method by 
myself and coworkers has shown it to have great value 
in many physiological and psychological researches. In 
order to make the method more readily available for 
investigators, and with the hope that thereby quantita- 
tive studies may be more generally made, the scattered 
material of the original papers has been assembled into 
the form herein presented. Since the work aims to 
serve rather as a manual than as an exposition of prin- 
ciples, only so much theoretical matter is included as is 
necessary to make intelligible the procedures adopted. 
E. G. M. 
BOSTON, April, 1912. 
iii 
798044 
