Biological material and poisoning

If it is considered that the deceased had been poisoned over an extended period prior to death, it is important to collect hair (plucked from the roots with the ends tied with thread at the scalp end) and nail specimens. The growing hair and nail can absorb many trace elements from the blood stream and these elements are permanently bound to the keratin. Knowing that the average rate of growth of human hair is approximately 1cm per month, sectional analysis of the hair from the root to the tip will produce a calendar of exposure to the element. 

It has to be admitted that decaying human organs have a rather unpleasant 

---