Miltons' Re-Agent

MILTONS' RE-AGENT

Metallic mercury is dissolved in its own weight of concentrated nitric acid (sp. gr. 1.42) and this solution diluted with an equal volume of water. This re-agent should be kept in a tightly-stoppered bottle, when it will usually retain its staining power for a long time. It is used as a stain for animal fibres. The mixed or separated kinds of fibres are covered with a few drops of Miltons' re-agent and gently warmed (not boiled). In Miltons' re-agent a brick-red colour will develop with silk, while rayons remain white or uncoloured. Copious fumes of red oxide of nitrogen are given off, so the solution of the mercury should take place under a hood.