ON THE ADULTERATION OF COCHINEAL. 61 
gathered from these gentlemen, a great part of the cochineals 
which come to Bordeaux are converted into zacatillee cochi- 
neal. There are persons in this town whose sole occupation 
this is. This cochineal is offered to the merchants at from 6, 
8 and 10 per cent, below the current price. Guibourt, as I 
before said, mentions this fraud as a certain proof that the 
black cochineal is superior to the gray. 
By examining the zacatillee cochineals of commerce atten- 
tively, knowing moreover that they are always sold below the 
current price, I thought that only two kinds of adulteration 
were possible ; the first might consist in rolling the cochineal, 
rendered moist, in a black heavy powder (manganese for ex- 
ample,) to change the color and increase the weight; the se 
cond, to deprive it of the whitish layer which covers it, by 
soaking it in boiling water, which at the same time must take 
a part of its coloring matter from it, which would be made 
use of. The first method hardly seems probable ; a part of 
the black dust becoming detached by rubbing would always 
betray the adulteration. The irregular form of this cochi- 
neal, and the roseate lustre which it presents, lead me to 
think that the second kind of supposed adulteration is the 
most likely. I am therefore of opinion, according to my 
experiments, that gray cochineal is treated with warm water 
to extract a part of its coloring principle, that by this im- 
mersion the insect is in great part deprived of the white 
powder which covers it, and is transformed into black za- 
catillee cochineal. Whether it is this or any other method 
which is put in practice, it is certain that the zacatillee co- 
chineal is less rich in coloring principle. It is sold as such 
in commerce ; but it often happens that zacatillee is adver- 
tised at 6 per cent., and that it is 10, 12, and sometimes 
more. Up to the present time the buyer has not possessed 
an easy method of appreciating the different degrees of 
adulteration. 
In the specimens which I procured from persons who re- 
tail cochineal, I found exactly the three qualities before 
vol. xi. — no. i. 6 
