Abstract
The peracetic acid-Schiff reaction was studied in the hair with a view to establishing its histochemical significance. Evidence was collected which favoured the view that the peracetic acid-Schiff reaction was not a general test for ethylenic linkages and that the Schiff reagent was not acting in its capacity as a specific reagent for aldehydes. The nature of this remarkable reaction was obscure, and consequently its histochemical validity at the present time seemed doubtful.