( 710 ) 
sense. If, moreover, we neglect for the small interval for which the 
formula holds, the variations of the quantities ZE, Z3 ete. with 
regard to the variation of Zj and also neglect the very small 
quantity e, the formula goes over in the very special interpolation 
formula which we know as the expression of the law of FECHNER: 
AR 
AE=C— . . . ° e e . ° (II) 
When applying this formula to physiological problems we generally 
do not measure the energy quantity / itself, but another quantity 
which (at least by approximation) is connected with that quantity 
by a linear relation. 
In order to make this formula which applies only for a very 
small increase of the stimulus, available for a greater interval, 
Frecuner has summated this expression over a larger interval. When 
executing this summation he neglected the small quantity ¢ and 
replaced in this way the summation by an integration. This gives 
formula (IL) the following form: 
BEER LO ee aa ee 
If this summation shall be correct, the same thing must take 
place from moment to moment. For the left-hand side of the equation 
this involves the special law, according to which the distribution 
of the transformed energy over its different forms is independent of 
the value of the increment of the stimulus. As the state of the 
system, the other circumstances remaining unchanged, is determined 
by the value of this increment, we can express this law also as 
follows: the distribution of the transformed energy over its different 
forms is independent of the state of the transformer. It is clear 
that this simple law of distribution, which we might call the law of 
the constant proportions, can only be correct by approximation. By 
means of ergographical investigations LEHMANN !) has tried to deduce 
this same law, for the contracting muscle, from the first principal 
law. This however, is only possible by means of the second prin- 
cipal law, which is itself a law of distribution. The summation of 
the energy quantities is beyond doubt. 
For the right-hand side of the equation this summation involves 
that C be constant throughout the interval over which the summation 
is extended. This constant contains the constant AK of formule (1). 
The value of this constant is determined by the nature of the 
transformer. Accordingly the summation involves this law: the 
1) LEHMANN, Körperl. Aüss. psych. Zustände, 1901. p. 191. 
