Since we last assembled here, and shortly after the last meeting of the session, the British Association met in our city. Though the first meeting of that body was held at York, yet the proposals and counsels which called it into existence, and led to its organisation, emanated from Edinburgh. It originated, in fact, from the suggestions of a distinguished former President of this Society, Sir David Brewster (then Dr Brewster), aided principally by two former secretaries of the Society, Professor Forbes and Sir John Robison.

While working at the histology of the tooth, it occurred to me that some light might be thrown on the vexed question as to the manner in which dentine grows, by observing what parts of a tooth are stained when an animal is fed on madder mixed with its food. In order to investigate this I examined the persistently growing teeth in three young rabbits, all of the same litter, which had been fed on madder (Rubia tinctorum) for two weeks. The first rabbit was killed immediately after being thus fed; the second was killed after feeding for two weeks on ordinary diet subsequent to the madder food; while the third was killed three weeks after feeding with, madder had been discontinued.

The principal subject of the author's research has been the comparative histology of the spleen in twenty-two different kinds of animals, embracing all the typical vertebrates from the fish to Man.

The capsule of a typical mammalian spleen, such as that of the cat, consists of two layers, the outer composed of ordinary fibrous tissue, the inner of nonstriped muscle. The splenic artery and vein, as they enter the organ at the hilum, are enclosed in a sheath formed by an inflexion of the capsule, and, like it, consisting of a fibrous and a muscular layer, the fibrous layer being next the vessels, and the muscular layer external to it, adjoining the pulp.

At the beginning of last year I proposed that a cable might be laid down in the sea, and, by changing the electric state of the cable, that vessels passing near or over it might be able by means of a detector on board to discover that they were in its vicinity, and hence to locate their position. Some experiments showed that the method was feasible, and that water offered no insurmountable difficulty; and having been assured that no known instrument could detect the currents that could, with our present machinery, be passed through a submarine cable, a series of exhaustive experiments were made, with the result that I have constructed two such instruments that will act through over 30 fathoms of water, and I have been unable to discover their like.

The apparatus which I have devised for the counting of bacterial colonies in roll-cultures, consists of a glass tube 15 centimetres long, the surface of which is divided by finely etched lines into square centimetres. The bore of this tube is such that the roll-culture tubes, which are of a uniform diameter, just slide without play within it. The ends of the tube are fitted into brass collars (Al, A2), which have inserted in them india-rubber rings (B1, B2). These india-rubber rings serve to retain the culture tubes in position during the process of counting. One end of the apparatus is adapted for grasping ordinary roll-culture tubes, the other for fixing the thin stems of Roux's tubes for anaerobic cultures.