INK-GALLS. 119 
such as that of the leaf-gall, his fingers will presently 
be stained with purple-black. He may wash his hands 
as much as he likes, but he will not wash away the 
stain, which soon looks as if it had been produced by 
spilling ink on the hands. There is reason for such an 
appearance, inasmuch as the staining liquid is really ink, 
though of a paler hue than that which is used for writing. 
FOREIGN GALLS, 
Ink Galls. Dead Sea Apple. 
Hungarian Gall. Galls of Cynips polycera. 
A little lemon-juice will soon discharge the colour, and 
then the soap and water will remove the last remnants 
of the stain. 
Ink is made by mixing a solution of the sulphate of 
iron (properly called green vitriol or copperas) with a 
decoction of certain oak-galls. Perhaps I may mention 
that a “decoction” signifies water in which any sub- 
