This test, as Dr. Oliver pointed out, discovers (a) the normal sugar; (b) the varying proportions of sugar which fill in the gap between the normal amount and that which characterizes diabetes mellitus, as in liver derangements and vaso-motor disturbances; (c) diabetic proportions.
It possesses the following advantages over Fehling's test:
1. It will detect sugar in any proportion in the presence of albumen, peptone, blood, pus, or bile, and as readily as in ordinary diabetic urine.
2. It gives no play of colors with uric acid.
3. It possesses portability, cleanliness, and stability.
Moore's, Trommer's, and Boettger's bismuth tests are all inferior in delicacy.—British Medical Journal.
CHEMICAL COMPOUNDS MADE BY COMPRESSION.
By M. W. Spring.
The author has previously shown the possibility of uniting the fragments of solid bodies by the sole action of pressure. He also established at the same time the possibility of forming chemical compounds by means of pressure. Thus he obtained cuprous sulphide by compressing a mixture of sulphur dust and copper; mercuric iodide, by compressing mercuric chloride with potassium iodide, etc. Finally, by compressing in the same manner mixtures of the filings of different metals, he formed alloys having for equal compositions the same melting points as those obtained by fusion.
The last mentioned facts certainly establish the possibility of causing bodies to enter into chemical reaction by the mere agency of a mechanical energy. This result is closely linked with another obtained during the course of the same investigation: the polymerization of certain simple bodies, e. g., sulphur, by the action of pressure. The author had drawn a general conclusion from his experiments, and had announced that matter takes, below a given temperature, a state corresponding to the volume which it is compelled to occupy.