E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
said to have sprung from the blood of Ajax; but how the blood of the mad boaster could produce this modest flower is past understanding. (Latin, viola; Greek, iov.)
As when stern Ajax poured a purple flood,
The violet rose, fair daughter of his blood.
Dr. Young: The Instalment.
Chemical test paper is steeped in syrup of violets; used to detect acids and alkalis. If an acid is present, it will change the violet paper into red, an alkali will turn the paper green. Slips of white paper stained with the juice of violets (kept from the air) will serve the same purpose. Litmus and turmeric are also used for similar purposes. The paper should be unsized.