There is another danger:  juries do not know the difference in the standing, character and attainments of doctors, so the tendency is always to find the man who will make the best appearance and testify the most positively for his side.  This is unfair to the expert, unfair to science, and unfair to the case.

The method for overcoming this difficulty that has received most sanction from students is that experts shall be chosen by the state and appear for neither side.  This, like most other things, has advantages and disadvantages.  State officials, or those chosen by the state, usually come to regard themselves as a part of the machinery of justice and to stand with the prosecuting attorney for conviction.  It will most likely be the same with state defenders.  No one who really would defend could be elected or could be appointed, and it would work out in really having two prosecutors, one nominally representing the defense.  A defendant should be left to get any lawyer or any expert he wishes.  No one can be sure that the state expert will be better than the others.  All one can say is that state experts may not be partisans, but, in effect, this would mean that they would not be partisans for the defendant.  The constant association with the prosecutor, the officers of the jail, the public officials, and those charged with enforcing the law, would almost surely place them on the side of the state.  Such men must be elected or appointed by some tribunal.  This brings them to the attention of the public and makes them dependent on the public.  The expert’s interest will then be the same as the interest of the prosecutor and the judge.

The prosecuting attorney is not a partisan.  His office is judicial.  He is not interested in convicting or paid for convicting, and yet, no sane person familiar with courts would think that the defendant could be safely left in his hands.  Assuming he is honest, it makes little difference.  Almost no prosecutor dares do anything the public does not demand.  Neither, as a rule, has he training nor interest to study any subject but the law.  The profounder and more important matters affecting life and conduct are a sealed book which he could not open if he would.  Very soon under our political system the expert business would gravitate into the hands of politicians, the last group that should handle any scientific problem.  I am free to confess the difficulties of the present system, but some other way may be even worse.  It must always be remembered that this country is governed by public opinion, that public opinion is always crude, uninformed and heartless.  In criminal cases there is no time to set it right.  The position of the accused is hard enough at best.  He is really presumed guilty before he starts.  Every lawyer employed to any extent in criminal practice knows that in an important case his greatest danger is public opinion.  He would not take the officers and attaches of the court as jurors, although they might be good men, for their interest and psychology would be always for conviction.