With regard to smaller bodies, these can scarcely be treated in any other way than by attaching a number of them to slips of glass at once, and in such a way as to make them mutually support each other. Thus in making horizontal and vertical sections of _foraminifera_, it would be impossible to slice them through unless they were laid close together in a bed of hardened Canada balsam, and first grinding away one side and then turning and rubbing down the other. My friend, Dr. Wallich, many years ago communicated to me the ingenious plan adopted by himself when mounting and turning a number of these minute objects together. The specimens being cemented with Canada balsam, in the first instance, to a thin film of mica, and then attached to a glass slide by the same means, when ground down to the thinness desired, the slide must be gradually heated just sufficiently to allow of the detachment of the mica-film and the specimen it carries; a clean slide with a thin layer of hardened balsam having been prepared, the mica-film is transferred to it with the ground surface downward. Its adhesion by drying having been complete, the grinding and polishing should be proceeded with; and as the mica-film will yield to the stone without any difficulty, the specimen now reversed in position may be further reduced to the requisite thickness for mounting as a permanent object. _Staining and Mounting Vegetable Tissues._--Bacteria I propose to treat of in a separate section. Vegetable tissues generally will first receive attention, and their differentiation is based on the employment of delicate gradations of colour stains. The more striking results are obtained by _Multiple Staining_, while the cell contents are rendered more palpable. On this account colouring media have been divided into _nuclear_, _plasmic_, and _specific_. The first are chiefly valued in proportion as they prove to have a selective affinity for the nuclei of cells, and leaving the protoplasm comparatively unstained. Such stains are needful for fresh and young tissues. On the other hand, _plasmic_ stains colour tissue uniformly, and are used to give a ground colour by way of contrast; and _specific_ stains are chiefly employed to distinguish certain elementary structures from the mass of cellulose which forms the basis of vegetable tissue, and which is also met with to a slight extent in animal membranes.