Mr. Gallagher.

sample having been bombarded by neutrons are transformed in many instances to radioactive atoms. These radioactive atoms will decay and emit characteristic radiations. By studying the emitted radiations, one can determine and trace quantities of elements in specimens.

Mr. Redlich.

This is a technique whereby certain elements are made radioactive as a result of being bombarded by neutrons; is that correct?

Mr. Gallagher.

Yes, sir.

Mr. Redlich.

This enables you to isolate certain elements for purposes of analysis; is that correct? Let me rephrase the question: Does this enable you to determine the presence of certain elements for purposes of analysis ?

Mr. Gallagher.

This enables you to determine and to measure the quantity of certain elements in a given specimen.

Mr. Redlich.

What is the advantage of the neutron activation technique over other methods of determining the presence of certain elements?

Mr. Gallagher.

Well, this method of analysis, because of its extreme sensitivity, offers a great advantage over more conventional procedures. Furthermore, chemical treatments of your samples subsequent to activation do not distort your results by contamination. If an acid, for example, is added to a specimen after irradiation which is. under study for the presence of antimony, and the acid itself contains antimony, it will not contain a radioactive form of antimony, and this is the form which is measured during the analysis.

Mr. Redlich.

Has neutron activation analysis been used in criminal investigation work, to your knowledge, Mr. Gallagher?

Mr. Gallagher.

It has been used in criminal investigative work.

Mr. Redlich.

Could you, for the sake of the record, give me a few examples of the types of situations in which it has been used--without reference to any particular case ?

Mr. Gallagher.

Neutron activation analysis has been used to determine the arsenic content in hair, urine, and fingernail scrapings, in a suspected arsenic-poisoning case.

Mr. Redlich.

Has it been--is it used as a method of determining whether or not a person has fired a weapon

Mr. Gallagher.

I do know that this technique has been used to attempt to determine if an individual has fired a weapon.

Mr. Redlich.

Do you believe that it is a technique which could be used under certain conditions to determine whether or not a person has fired a weapon?

Mr. Gallagher.

I do believe that it is a technique which can be used to determined if a person has fired a weapon or handled a recently fired weapon.

Mr. Redlich.

Have you yourself, Mr. Gallagher, ever testified in court with

regard to the results of a neutron activation analysis?

Mr. Gallagher.

No, sir.

Mr. Redlich.

Now let us turn, Mr. Gallagher, to the specific investigation that we are concerned with in this inquiry. Are you familiar with any neutron activation analyses which were conducted in connection with the assassination of President Kennedy?

Mr. Gallagher.

Yes, sir.

Mr. Redlich.

Could you describe what they were?

Mr. Gallagher.

Neutron activation analyses were conducted at Oak Ridge National Laboratory, Oak Ridge, Tenn., on the paraffin casts from the right hand, the left hand, and the right cheek of Lee Harvey Oswald.

Mr. Redlich.

May I interrupt you there, Mr. Gallagher? Your determination that these were the casts from the right and left hand and right cheek of Lee Harvey Oswald was based upon information given to you and is not based upon your own personal knowledge; isn't that correct?

Mr. Gallagher.

It is based upon knowledge which I obtained from an official Bureau report.

Mr. Redlich.

The record would indicate that these casts were made in Dallas, and were made in connection with tests performed by the Dallas police. And then subsequently they were forwarded to the FBI in Washington. That is our understanding of the manner in which the casts were made and placed into the possession of the Federal Bureau of Investigation. Do you have any information to the contrary?