PS Found some info re ACARUS CROSSII (the mites created in the lab) by Andrew Crosse at this link

Andrew Crosse, an English country gentleman, in 1837 made the following experiment, which excited much publicity: he mixed two ounces of powdered flint with six ounces carbonate of potassa, fused them with heat, reduced the compound to powder and dissolved it in boiling water, obtaining silicate of potassa. This he diluted in boiling water, slowly saturating with hydrochloric acid.

This he then subjected to "a long-continued electric action, through the intervention of a porous stone" (?) in an effort to form crystals of silica. This did not happen, but on the fourteenth day of the experiment, he observed a few minute whitish lumps on the middle of the electrified stone. By the eighteenth day, these had grown and stuck out seven or eight filaments. On the twenty-sixth day, they had become perfect insects, standing erect on a few bristles, which were their tails....

That "porous stone" variable is suspicious. Could microscopic insect eggs /larvae have been lurking about in those pores? Did C19 experimenters have the equipment/expertise to rule out that possibility?