A homogeneous mucilage will serve for marbling much better, than that, which is produced by swelling, because the latter has an injurious influence on the fine distribution of color for veined, comb and other edges. Although the surface of such a size seems to be smooth, the eye will discover on closer investigation the undissolved bodies in the small granules of the size. The mucilages obtained by swelling are always milky-cloudy and never permit the colors distributed upon them to expand with the same purity and smoothness as the homogeneous varieties, on account of the small granules hindering the drawing of the colors on their surface. On the other hand there are varieties of size, which are very viscous on account of a too homogeneous mucilage and therefore from their nature are not adaptable to any kinds of edging which must be drawn by the stylus. The colors can simply not be drawn on the surface, because this very viscous mucilage is drawn along by the stylus instead of being cut by it. In investigating the different varieties of size I have noticed a very surprising action of the extremely viscous mucilage, which nearly confused me for the moment. I have scalded with boiling water plantago-psyllium (flea-bane) and have beaten it with wicker-rods tied together so as to produce in a better manner, the mucilage found on the outside of the seed. After cooling it off, I filtered it through a linen cloth and poured it into the trough but have not waited till the very viscous thread of mucilage parted after the trough was filled to a certain height, but have placed the vessel on the floor and to my utter surprise the thread of the size spread out and reached the vessel on the floor, becoming gradually thicker until finally the whole size flowed in a white stream with great velocity over the rim of the trough (2 inches high) and returned to the vessel standing on the floor until the trough emptied. This was done in a very short time. The cause of my surprise was in the very consistent mucilage which took along ever-increasing quantities of the size and finally entirely emptied the trough. Prepared colors, which on a less viscous size are normally distributed expand with a greater velocity to a greater extent on a more viscous size and therefore become pale. For such kinds of sizes the earth colors are preferable but only for marbled edges.