Féré, Travail et Plaisir, Chapter XIII.
Travail et Plaisir, p. 175. It is doubtless true of the effects of odors on the sexual sphere. Féré records the case of a neurasthenic lady whose sexual coldness toward her husband only disappeared after the abandonment of a perfume (in which heliotrope was apparently the chief constituent) she had been accustomed to use in excessive amounts.
It is perhaps significant that many colors are especially liable to produce skin disorders, especially urticaria; a number of cases have been recorded by Joal, Journal de Médecine, July 10, 1899.