THE INFLUENCE OF SECONDARY RESISTANCE 87 
made to keep conditions of tissue resistance and cathode 
surface approximately uniform. On the contrary, these 
conditions were purposely made to vary widely from one 
experiment to another. I feel, therefore, that they cover 
the range of variation likely to occur in ordinary experi- 
mentation. 
These data seem to me to show that in the hands of 
a careful experimenter, who will take pains to keep his 
conditions of stimulation as uniform as possible, quanti- 
tative results of great value may be obtained without the 
labor involved in taking account of secondary resistance 
and cathode surface. By the use of the method out- 
lined in previous chapters the strengths of stimuli em- 
ployed in any given case may be expressed in terms of 
stimulation units, and if the conditions of experimenta- 
tion, such as the nature of electrodes used, distance be- 
tween them, and method of applying them, are carefully 
described, other experimenters can duplicate the stimuli 
very closely. Certainly this method allows comparisons 
of much greater accuracy than can be made by the ex- 
isting methods of describing stimuli. It is highly im- 
portant, however, that investigators attempting to use 
induction shocks quantitatively recognize fully the limi- 
tations upon accuracy which are involved in disregard- 
ing the factors under discussion. So long as there is no 
effort to draw ' conclusions which are not warranted by 
the degree of accuracy actually obtained, no harm will 
