Fig. b. Mag. 260 diams.
Most of the brown sugars of commerce are infested by this pest, which is of a size sufficiently large to be visible to the naked eye. The following method of proceeding will lead to its detection:
Dissolve 2 or 3 teaspoonfuls of sugar in a large wineglass of tepid water, and let the solution remain for an hour or so, at the expiration of which time the acari may be found, some on the surface of the liquid, some attaching themselves to the sides of the glass, and some at the bottom, mixed up with the copious and dark sediment, made up of fragments of cane, woody fibre, grit, dirt, and starch granules, which usually subside on dissolving even a small quantity of sugar in hot water. When first hatched this acarus is hardly visible.
Acari of all sizes—that is, in all stages of growth—may be met with in most samples of sugar.
Dr Hassall, in seventy-two samples of sugar which he examined, found sixty-nine containing them.
Fig. c.
Acarus Siro, the cheese-mite (fig. c). The dry and powdery parts of decayed cheese, which by careful watching may very frequently be seen in movement, consist almost wholly of this insect and their eggs in different stages of development. The cheese-mite can hardly be seen without the aid of the microscope. They are very tenacious of life, even when kept without food. Mr Blyth says that under these circumstances “it is no uncommon sight to see them killing and devouring each other; and that cheese is rapidly destroyed by them; they crumble it into minute pieces, and emit a liquid substance which causes the decayed parts to spread speedily.” They may be destroyed by being exposed to a strong heat, or by putting the cheese for a short time in whisky.
Fig. d.