ANIMAL PRODUCTS 145 



internal animal product is gall, which is a bitter- 

 tasting fluid secreted by the liver ; that obtained 

 from the ox being used by artists in conjunction 

 with water-colour paints, while the gall from the 

 carp is used by the Turks as a green pigment. The 

 commodity known as ivory-black, which is prepared 

 by calcifying ivory refuse, is used also by artists 

 in the form of a paint, and sepia is a brown pigment 

 prepared from the fluid secreted by the glands of 

 the cuttle-fish, a creature that yields also the cuttle- 

 bone of commerce (an internal calcareous plate 

 taking the place of a backbone) which, when finely 

 powdered, is used as a tooth-powder, and, under 

 the name of pounce, was formerly employed to 

 absorb the surplus moisture of wet ink, until its 

 use was superseded by blotting-paper. 



The bright red dye known as carmine is obtained 

 by boiling the dried bodies of cochineal insects in 

 water, and then adding some alum in order to 

 precipitate the colouring matter (about seventy 

 thousand of the creatures being required to make 

 one pound of the commodity) ; while in former 

 days the insects were used as a medicine for the 

 treatment of whooping-cough. A very useful 

 varnish, known as lac, is obtained from the small 

 Coccus lacca insect ; and we read in CasselVs Natural 

 History that * the dye used in the manufacture of 

 the celebrated " Tyrian purple " of the ancients 

 was obtained from certain species of Murex. The 

 small shells were bruised in mortars and the animals 

 of the larger ones were taken out.' The dog- 

 winkle (Purpura lapillus) yields a white fluid 



K 



