Quinine used as invisible ink

A carte-de-visite showing a design and the word 'Quinine' written out on a piece of paper using a disulphate of quinine. According the text below, this is a 'Photograph of an invisible Design painted in solution of Disulphate of Quinine. Owing to the destruction of the chemical rays by the Quinine the parts coated with the latter photograph as if Black'.

Photographed by J. Fisher of 108 Westbourne Grove, London.