COLOUR-PRODUCING INSECTS. 57 



carminium, and contain a greater quantity of 

 grease, etc. This is so true that if the greasy 

 matter be previously separated by pressure from 

 Coccus polonicus, this insect can be employed weight 

 for weight with the same advantage as the genuine 

 cochineal. 



Carmmium may be obtained by treating pul- 

 verized cochineal, first by ether to extract the 

 greasy matter, and then by alcohol. The product 

 thus obtained is treated once more in the same 

 manner, when, by evaporation of the alcohol, car- 

 minium is deposited as a granular substance of a 

 red-purple colour. If carminium be combined with 

 oxide of lead, we obtain a violet compound, which, 

 when decomposed with sulphuretted hydrogen, 

 yields a transparent colourless liquid, by the evapo- 

 ration of which a new substance is deposited in 

 colourless crystals. These absorb oxygen from the 

 air and become carminium. 



In August 1856, M. Belhomme made the beau- 

 tiful discovery of carminium in the vegetable king- 

 dom ; he found it in the petals of a plant of the 

 Orchidse family, the Monarda didyma, L. This 

 plant, which has been known to horticulturists for 

 some time, is a native of North America. When 

 its petals are placed in water, they yield to the 

 liquid a crimson colouring matter in every respect 

 similar to the carminium of the cochineal. Some 



