Very few, if any, higher life forms existed that did not have some sort of submicroscopic parasite afflicting them.
These colloid substances have a submicroscopic or micellian structure; they are web-like, porous and absorb water eagerly.
In any case, a microscope would have done Brown little good in trying to detect the submicroscopic beings of the Rell.
submicroscopic sub·mi·cro·scop·ic (sŭb'mī-krə-skŏp'ĭk)
Too small to be visible under the most powerful optical microscope.