1 8 INDUCTION SHOCKS 
v. Fleischl,* in 1875, proposed a method of calibrating 
the inductorium in which for the galvanometer deflec- 
tion was substituted the threshold contraction of a 
nerve-muscle preparation. In this calibration the de- 
creases in stimulating value which result from moving 
the secondary coil outward were compensated by in- 
creasing the current through the primary coil, the in- 
creases required being taken as the measure of the 
change in stimulating intensity resulting from the move- 
ment of the secondary. This method has the advantage 
of being available in situations where no galvanometer 
can be obtained. Its greatest importance lies, however, 
in confirming the assumption of Fick and of Kronecker 
that the physiological intensities of break induced cur- 
rents are proportional to the galvanometer deflections 
they produce. 
Wertheim-Salomonsonf has recently described a 
method for obtaining a physiological calibration in 
which variations in the primary current are avoided. 
He places the nerve of the nerve-muscle preparation to 
be used as an indicator in one branch of a divided sec- 
ondary circuit, and in the other branch places a re- 
sistance equal to that of the nerve. (See Fig. 4.) The 
resistance of the divided circuit is then one-half that of 
* v. Fleischl: Sitzb. d. k. Akad. d. Wissensch. Wien, 1875, Bd. 
Ixxii, Abth. III. Also Ges. Abh., 1893, S. 475. 
t Wertheim-Salomonson: Zeitschr. f. Elektrother. I., 1899, S. 97. 
