What is "hygroplasm"

Hygroplasm \Hy"gro*plasm\, n. [Gr. ? wet + ? form, mold.] (Biol.) The fluid portion of the cell protoplasm, in opposition to stereoplasm, the solid or insoluble portion. The latter is supposed to be partly nutritive and partly composed of idioplasm.

n. (context biology archaic English) The fluid portion of the cell protoplasm, in opposition to stereoplasm, the solid or insoluble portion.