Mr. Dulles. We want to thank you very much.
Mr. Eisenberg. There is one further question I have.
When you made your examination, were you aware of the conclusions which any other examining agent or body had come to?
Mr. Nicol. No. I of course was aware of the fact that tests were conducted. However, I was not aware either through the press or any other media as to the conclusions. This represents my own personal conclusions without benefit of any other knowledge.
Mr. Eisenberg. And do you know at this point what any other body has come to in the way of conclusions?
Mr. Nicol. No, sir.
Mr. Dulles. I wonder if you would be willing to give us your views as to the effectiveness of paraffin tests?
Mr. Nicol. I have used the paraffin test both in case work and in experiments, as an investigative aid. However, I have a very low level of confidence in it—either as a positive or negative, as far as that's concerned.
Experimentally, as the literature well demonstrates, it is possible to fire a gun and get nothing on the hands. It is also possible to take people at random off the street and test them with the reagent which is not specific for powder and find all kinds of reactions. And while there are some "experts" who—and I say that with quotes—who allege that they can differentiate one product from another, actually the end product of the oxidation of diphenylamine is a definite quinoid structure, which has only one blue color, and I am not sure how they make this differentiation. I cannot do it.
I have used it as an investigative aid with positive results if and when I find in the cast a particle of powder that I can definitely identify as powder—not just simply the reaction, but something I can take out, put it under the microscope and I can say this is a particle of powder. Then I will say that this hand has been in the presence of the discharge of a weapon.