220 A SKETCH OF 



Cochineal from Oaxaca alone, is now valued at 500,000, 

 an enormous sum, if we recollect that a pound costs about 

 thirty shillings, and contains some 70,000 insects. The 

 provinces in which the culture of Cochineal is most largely 

 carried on, are Oaxaca, Tlascala and Guanaxuato. The 

 Tuna Cactus fOpuntia Tuna) is raised in fields in the 

 great mayorals, which are called Nopaleros, from the 

 Spanish name of the Opuntia f Nopal J. The Cochineal 

 Cactus fOpuntia coccinelliferaj as it is called, is used 

 only in the West India Islands and Brazil. It is necessary 

 to renew the plantations frequently, as the insect rapidly 

 exhausts the juices of the plant, so that it dries up and 

 dies. The traders distinguish two kinds of Cochineal, the 

 grana fina and the grana sylvestre ; the former is richer 

 in colouring matter and its colour is brighter, the substance 

 which invests the insects is also more pulverulent, while 

 in the latter it is flocculent. However, it has not yet 

 been made out whether these differences indicate two 

 different species of the insect, or depend on a difference in 

 the mode of culture and the species of plant on which 

 the animal lives. When the animals are fully developed, 

 they are swept from the branches of the plant with a 

 squirrel's tail, and killed by the heat of the sun or hot 

 water, dried and brought into the market. We prepare 

 from them the costly carmine by the addition of a prepa- 

 ration of tin, and the carmine-lake (Florentine lake) by a 

 combination with pure alumina. 



While the ugly form, the splendour of the blossom, and 

 the manifold uses of the Cactus plants attract general interest 

 in a high degree, they are not less interesting, in a narrower 

 sphere, to the Botanist. Zoologists have at all times found 

 in the examination of monstrosities and aberrant forms, rich 

 material toward the clearing and expanding of their know- 



