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A paper read by Mr. Thomas Bolton at a recent meeting of the Birmingham Natural History Society, "On the Examination of Rotifers and Infusoria under the Microscope," suggests a remark or two which may be useful as hints to some of our readers.

Most forms of compressorium are useless, all are expensive. Those who try the following will be surprised at the efficiency of the apparatus. Two pieces of thin glass are cemented on to a glass slip in the shape of the letter L, but with the two strokes of the letter about equal in length, and another thinner and longer one is fixed longitudinally, thus L—. The L serves to retain in position a square slip of cover glass placed, of course. not on the L but inside it; the horizontal piece, which should be ground to a bevel on its top edge before fixing it, serves to carry a fine needle, the point of which is inserted beneath the edge of the cover glass. This point being tapered, it is easy to increase or diminish the thickness of a film of water carried between the cover and the slip: by pushing the needle further in or out, and so to form a cheap and effective compressorium.

Those who possess a Ross's four-tenths condenser will find the arrangement of stops marked O over B give the most perfect dark background illumination, available, by unscrewing the top lens of the combination, for low powers.

The beauty of Rotifers and Infusoria seen by this illumination is immensely enhanced by feeding them with carmine, sparingly supplied to the water by drawing a camel-hair brush, charged with some of the pigment, along its surface. In a few minutes the stomachs of Rotifers and the cavities of Infusoria are painted with the most glowing colour, while the ciliary currents to and from the animals are traced out in equally brilliant lines.

The vases of all the thecated Rotifers are tinged with the colour upon which their tenants are fed. Hence evidently the material out of which they are constructed is a product elaborated from the food of the animal.

Microscopists will be glad to hear of a really good low priced revolving microscope table, which is accurately described in the maker's advertisement as "sturdy and substantial." The legs, which form a tripod, are handsomely cast in iron and bronzed: the top "is made of a thick slab of slate. Without being inconveniently large it is large enough for all practical purposes. The microscope and lamp may be readily adjusted at one side of it, and then quietly moved round without readjustment to other students sitting round the table. There is room on the table for a compound microscope and lamp, a simple or dissecting microscope for preparing objects for the larger one, or for biological laboratory work, and for note-book and text-book, or other writing materials, either of which may be successively brought round to the student as it may be required, by the mere revolution of the table. The top being made of slate is very serviceable and easily cleaned. An ornamental cover over the slate top when the table is not in use for microscopical work will make it fit for a place in the drawing room. The table is also made with a solid mahogany top, the centre of which is inlaid with leather to meet the wishes of those who prefer a wood to a slate top. The manufacturers are Messrs. Hassall and Singleton, ironfounders, Birmingham, who have arranged with Mr. T. Bolton, 17, Ann Street, Birmingham to supply retail customers.