THE PURPLE OF THE ANCIENTS. 241 
near a painter's shop, as though a colour had been extracted from 
the mollusk, and kept in the shell for sale. 
Lesson thinks that the purple of the Tyrians was also pro- 
cured from the common Janthina. When one of the mollusks 
which produce this purple dies, not only is that part which con- 
tains the colouring matter tinted, but all the surrounding tissues. 
It has often been remarked by the curators of museums that 
alcohol and other preservative liquids in which specimens of these 
mollusks are kept, become tinted with various shades of purple. 
Until lately, we have been ignorant as to the whereabouts of the 
organ which secreted this colouring matter. Many naturalists 
supposed that the liquid in reality consisted of the juices which 
supplied the stomach with its digestive property. Others, who 
were nearer the truth, believed that there was a special organ for its 
secretion. M. Lacaze-Duthiers has given his attention to the subject, 
and has discovered that, beneath the mantle between the intestinal 
canal and the respiratory organs, there is a white band, in which 
the liquid is secreted. This organ scarcely differs either in position 
or shape in any of the species. The liquid is faintly yellow, and 
when submitted to the action of the sunlight, as we have already 
said, it passes through green to purple, which becomes deeper 
and deeper. The most disagreeable odour is exhaled during 
this process, which may be compared to burnt onions or assa- 
foetida. The smell is retained by the fabric for a long time, and 
even after a year has elapsed the scent is perceived when the 
material is moistened. When the purple fabric is washed the first 
time, it loses its colour a little, but this is almost inappreciable, 
and ever after it is “fast.” So the sailor's idea of marking his 
linen with it was excellent. In its yellow or green condition it 
can be washed out. M. Lacaze-Duthiers has often, in gathering 
the liquid from the gland, touched his finger-nail with it; and so 
strong is the dye, that the nail: would remain coloured for five 
weeks. 
Probably the property which rendered the dye so valuable 
was not only its brilliant colour, but the fact that the sun’s light 
did not injure it. All our purple and mauve colours are almost 
immediately affected; but the purple cloak of a Roman dandy, 
as he promenaded along the thronged terraces of the great city, 
O 
ie 
