What prolonged boiling and the aid of bicarbonate of soda leave almost intact the fly's grubs quickly turn into fluid, even as the flesh worms fluidify hard-boiled white of egg. This is done in each instance without violence, probably by means of a special pepsin, which is not the same in both cases. The liquefier of meat has its own brand; the liquefier of the bolete has another sort. The plate, then, is filled with a dark, running gruel, not unlike tar in appearance. If we allow evaporation free course, the broth sets, into a hard, easily crumbled slab, something like toffee. Caught in this matrix, grubs and pupa perish, incapable of freeing themselves. Analytical chemistry has proved fatal to them. The conditions are quite different when the attack is delivered on the surface of the ground. Gradually absorbed by the soil, the excess of liquid disappears, leaving the colonists free. In my dishes, it collects indefinitely, killing the inhabitants when it dries up into a solid layer. The purple bolete (Boletus purpureus, FRIES), when subjected to the action of the maggots, gives the same result as the Satanic bolete, namely, a black gruel. Note that both mushrooms turn blue if broken and especially if crushed. With the edible bolete, whose flesh invariably remains white when cut, the product of its liquefaction by the vermin is a very pale brown. With the oronge, or imperial mushroom, the result is a broth which the eye would take for a thin apricot jam. Tests made with sundry other mushrooms confirm the rule: all, when attacked by the maggot, turn into a more or less fluid mess, which varies in color. Why do the two boletes with the red tubes, the purple bolete and the satanic bolete, change into a dark gruel? I have an inkling of the reason. Both of them turn blue, with an admixture of green. A third species, the bluish bolete (Boletus cyanescens, BULL., var. lacteus, LEVEILLE), possess remarkable color sensitiveness. Bruise it ever so lightly, no matter where, on the cap, the stem, the tubes of the undersurface: forthwith, the wounded part, originally a pure white, is tinted a beautiful blue. Place this bolete in an atmosphere of carbonic acid gas. We can now knock it, crush it, reduce it to pulp; and the blue no longer shows. But extract a fragment from the crushed mass: immediately, at the first contact with the air, the matter turns a most glorious blue. It reminds us of a process employed in dyeing. The indigo of commerce, steeped in water containing lime and sulfate of iron, or copperas, is deprived of a part of its oxygen; it loses its color and becomes soluble in water, as it was in the original indigo plant, before the treatment which the plant underwent. A colorless liquid results. Expose a drop of this liquid to the air. Straightway, oxidization works upon the product: the indigo is reformed, insoluble and blue.