184 Charles W. Hargitt 
why under conditions as nearly identical as they can be made 
should two, or any number of specimens react in such variable 
manner? According to the theory there should be the closest 
possible similarity. Yet this rarely if ever is the case; indeed, it 
is just the contrary, as the foregoing facts clearly show. In chem- 
ical and physical experiments the experimenter proceeds upon the 
assumption that given constancy of conditions he rightly antici- 
pates constancy of results. Indeed, he may predict with mathe- 
matical certitude both the qualitative and quantitative character 
of the results. But this is just what the experimenter in problems 
of organic behavior can never predict, except in the most limited 
degree, and for but few organisms. And even then the results 
are far from certain exponents of this theory. To quote an expres- 
sion from a well-known experimenter—‘‘all the processes in our 
organism which can be explained on mechanical principles are as 
little phenomena of life as the movement of the leaves and branches 
on a tree when shaken by a storm” (Bunge). 
On the other hand, if we may regard these organisms, not as 
mere machines, automata, but as individual beings endowed 
with an organization, both physical and physiological, capable 
of self-coordination and direction, whether from external or inter- 
nal stimulation, or from pure spontaneity, then these variable 
phenomena of behavior are only such as conform to natural 
expectation. They form an integral part of that living world, 
from monad to man, whose correlated behavior, in its ultimate 
essence, differs relatively according to the complexity of the organ- 
ism concerned. | 
In common with a growing body of students of behavior the 
writer is forced to regard the tropism explanation, whether ap- 
plied to plant or animal, as but partial and superficial. The 
cases in which it has found its best illustrations have not stood 
the test of severe analysis. It is more than ever evident that, 
though we admit the intimate relation of chemical and physical 
processes, to every aspect of behavior, they are not of themselves 
explanatory except in the most partial way. Indeed it may well be 
questioned whether the all but universal disposition to explain 
the organic in terms of mechanics is not an actual reversal of 
