coccus 439 



a discharge of bloody urine. The principle use of cantharides is the 

 application, externally, of the cerate as a blistering plaster. It is 

 seldom used as a rubefacient, but as an epispastic or vesicant it is to 

 be preferred of all substances of this class. Its blistering action termi- 

 nates in a copious secretion of serum under the cuticle. Dose: ^ gr. 

 (0.03 Gm.). 

 OFFICIAL PREPARATIONS. 



Ceratum Cantharidis (32 per cent.)- 



Cpllodium Cantharidatum (60 per cent.). 



Tinctura Cantharidis (10 per cent.), Dose: I to 5 TIJ> (0.065 to -3 n"l) 



606. COCCUS. COCHINEAL 

 COCHINEAL BUG. RED SCALE INSECT 



The dried female insect, Coc'cus cac'ti Linne. (Fam. Coccidas), enclosing the 



young larvae. 



HABITAT. Mexico, Central America, and Northern South America (origi- 

 nally), and Spain and Algiers (introduced); feeds on various cacti, 

 especially upon Opuntia coccinilifera. 



COLLECTION. Only the females (wingless) are used; they are brushed 

 off from the food-plant, and, if alive, are killed by heat (hot water 

 or oven). The cochineal insect is cultivated on a large scale, and 

 large quantities are annually exported from Mexico and Peru. Hum- 

 boldt estimated that 800,000 pounds of coccus (each pound represent- 

 ing 70,000 insects) were annually imported into Europe. 



DESCRIPTION. The females (which alone are used) are small, wingless, 

 oval, dull purplish-brown insects, convex above, about 4 mm. (^ in.) 

 long, covered, when alive, with a white cottony 



' : - secretion. When the insects are dead and dry, this 

 "cotton" rubs off, and the crushed insects yield a 

 dark red powder; odor faint, taste slightly bitter. 



VARIETIES. These are: (i) silver, recognized by the 

 presence of a soft, silvery white powder contained 

 in the furrows and wrinkles; it appears to be a fatty 

 substance as it melts on the application of heat, 

 and the insects lose their silvery appearance. This Fl J?- 259^ Cochineal 



J Fr Bug (Coccus cacti) 



variety is said to be the mature and fecundated Liim6 (Original). 

 insect. (2) Black cochineal, of a reddish-black 

 color, nearly devoid of silvery powder, is supposed to be the 

 female exhausted by propagation. (3) Granilla, an inferior kind 

 composed of small and imperfect insects. 



ADULTERATION. The silvery gray variety with carbonate or sulphate of 

 barium and lead; the black cochineal with graphite, ivory black, or 

 manganese dioxide. " When completely incinerated, cochineal should 

 leave not more than 5 per cent, of ash." 



