We may remark that with this apparatus we obtain the maximum of useful effect, seeing that the work developed is represented by the total head of the water diminished simply by losses of charge due to friction in the pipes. In other apparatus the loss of charge is much less, since the flushing is broken by a receiver. Putzeys' apparatus, therefore, with a much less discharge of water, is capable of producing an effect superior to that of similar apparatus. On account of its simplicity and plain character, there is no need of precision in the installation of this apparatus, and horizontality, even, is not a _sine qua non_ for its perfect operation. The siphon is very easily cleaned, and this is a great advantage, since it permits of utilizing sewage matter for filling the flushing reservoir.--_Chronique Industrielle._ * * * * * PEPSIN. By A. PERCY SMITH, F.I.C., F.C.S., Rugby. The method usually adopted for estimating the peptonizing power of pepsina porci consists in dissolving 1 to 2 grains in 8 to 12 ounces of water, to which 40 to 60 minims of hydrochloric acid has been added. 500 to 1,000 grains of hard-boiled white of egg, granulated by rubbing through a wire sieve, is immersed in the liquid, and the whole kept at 98° to 130° F. for four hours, when the undissolved albumen is filtered off through muslin, and, after partial drying, is weighed to ascertain the amount dissolved. The variable numbers above quoted embrace various formulæ recommended by different experimenters. This method of analysis is excessively crude and untrustworthy. When hard-boiled white of egg is kept in warm water, it absorbs a considerable quantity of that menstruum, as much as several units per cent.; consequently, on weighing the residual albumen, you may find that the weight is greater instead of less than that with which you started, the gain in weight due to absorbed water more than counterbalancing the loss obtaining through solution, as has happened with indifferent samples of pepsin. Then who shall say when, by simple air drying, the albumen has regained its former condition? The enormous quantity of albumen is foreign to the usual habits of the scientific analyst, and involves an enormous waste of time in manipulation.