defined it best. It consists in trying to keep constant the complex
of conditions demonstrated to be necessary for the realization of a
given effect. It consists in varying these conditions, in isolating one
from the other in a numerically determinable order, and finally,
in establishing the accompanying changes with regard to the effect,
in a quantified or countable order.

I can not here say anything further to show that this is the sole
correct method of establishing the necessary principles of our science.
The aim is only to test the practicality of this method in the routine
of a criminal case, and to see if it is not, indeed, the only one by
which to attain complete and indubitable results. If it is, it must
_*be of use_ not only during the whole trial--not only in the testing
of collected evidence, but also in the testing of every individual
portion thereof, analyzed into its component elements.

Let us first consider the whole trial.

The _*effect_ is here the evidence of A's guilt. The complex conditions
for its establishment are the collective instruments in getting
evidence; the individual conditions are to be established by means
of the individual sources of evidence--testimony of witnesses,
examination of the premises, obduction, protocol, etc.

_The constantification of conditions_ now consists in standardizing
the present instance, thus: Whenever similar circumstances are
given, i. e.: the same instruments of evidence are present, the evidence
of guilt is established. Now the accompanying changes with
regard to the effect, i. e.: proof of guilt through evidence, have to