The chromatin substance increases in amount; the thread stains moie deeply, and in most cases presents a homogeneous appearance.
Cellulose has an affinity for acid stains, pectic substances for basic stains.
But the material was also subject to other defects, such as moisture lurking between the layers, which might be detected by strokes of the mallet; spots or stains; and spongy strips (taeniae), in which the ink would run and spoil the sheet.
Cleavage sheets are frequently disfigured and rendered of little value by brown, red or black spots and stains, often with a dendritic arrangement of iron oxides.
Usually the cytoplasm shows a marked affinity for the acid stains, but the different bodies found in the cell may show great variation in their staining reactions.