Let us go even further and assume that they have generated a reasonable doubt in the mind of the jury as to the defendant's responsibility at the time he committed the offence.

What generally occurs?
Not, as one would suppose, an acquittal, but, in nine cases out of ten, a conviction in a lower degree.
The only usual result of an honest claim of irresponsibility on the ground of insanity is to lead the jury to reduce the grade of the offence from murder in the first, entailing the death penalty, to murder in the second degree.

The jury have no intention of "taking the chance" involved in turning the man loose on the community and their minds are filled with the predominating fact that a human being has been killed.
They have an idea that it is as easy to get "sworn out" of a lunatic asylum as they suppose it is to get "sworn into" one, and they know that if the prisoner is found to be insane when sent to State's prison he will be transferred elsewhere.

They, therefore, as a rule, waste little time upon the question of how far the defendant was irresponsible within the legal definition when he committed the deed, but convict him "on general principles," trusting the prison officials to remedy any possible injustice.

The jury in such cases ignore the law and decline either to acquit or to convict in accordance with the test.