Another booklet in this series, _Neutron Activation Analysis_, discusses
a new process by which microscopic quantities of many different
materials may be analyzed accurately. Neutron irradiation of these
samples changes some of their atoms to radioactive isotopes. A
multichannel analyzer instrument gives a record of the concentration of
any of about 50 of the known elements.
One use of this technique involved the analysis of a hair from
Napoleon’s head. More than 100 years after his death it was shown that
the French Emperor had been given arsenic in large quantities and that
this possibly caused his death.
The ways in which activation analysis can be applied to medical
diagnosis are at present largely limited to toxicology, the study of
poisons, but the future may bring new possibilities.
Knowledge is still being sought, for example, about the physiological
role played by minute quantities of some of the elements found in the
body. The ability to determine accurately a few parts per million of
“trace elements” in the various tissues and body fluids is expected to
provide much useful information as to the functions of these materials.