Small objects immersed in gum solutions are frozen and in condition for cutting in less than one minute. The method of using this microtome can be understood by reference to the illustration. A represents a revolving plane, by which the thickness of the section is regulated, in the center of which an insulated chamber is secured for freezing the tissue. It resembles a pill-box constructed of metal. A brass tube enters it on each side. The larger one is the supply tube, and communicates with the pail, a, situated on bracket, s, by means of the upper tube, t. To the smaller brass tube is attached the rubber tube, t b, which discharges the cold salt water into a pail placed under it. (See b.) The salt and water as it passes from pail, a, to pail, b, is at a temperature of about zero. The water should not be allowed to waste. It should be returned to the first pail for continual use, or as long as it has freezing properties. As a matter of further economy, it is necessary to limit the rate of exit of the freezing water. This is regulated by nipping the discharge-tube with the spring clothes pin supplied for the purpose. Should the cold within the chamber be too intense, the edge of the knife is liable to be turned and the cutting will be imperfect. When this occurs the flow of water through the chamber is stopped by using the spring clothes-pin as a clip on the upper tube. In order to regulate the thickness of the tissue to be cut a scale is engraved on the edge of the revolving plate, A, which, in conjunction with the pointer, e, indicates the thickness of the section.--_Microscopical Journal_. * * * * * THE ST. GOTHARD TUNNEL.--It appears that the traffic through the St. Gothard Tunnel has increased, since the inauguration of through international services, to such an extent that the Company have already obtained sanction for laying the second pair of rails in the tunnel. The Great Eastern Railway Company has increased its steamer traffic, and built additional station accommodation at Harwich. * * * * * VINCENT'S CHLORIDE OF METHYL ICE MACHINE. Chloride of methyl was discovered in 1840 by Messrs. Dumas and Peligot, who obtained it by treating methylic alcohol with a mixture of sea salt and sulphuric acid. It is a gaseous product at ordinary temperature, but when compressed and cooled, easily liquefies and produces a colorless, neutral liquid which enters into ebullition at 237.7° above zero and under a pressure of 0.76 m. [Illustration: VINCENTS ICE MACHINE. FIG. 1.--THE FREEZER (Longitudinal Section).]