Picric acid is a delicate and often a convenient test. The dry acid may be dissolved in the urine, or a saturated solution used into which the urine may be slowly dropped, each drop making a slight whitish cloud as it slowly falls through the yellow solution. The iodo-hydrargyrate of potassium is perhaps the most delicate test of all: Potassii iodidi, 3.32 gm.; Hydrarg. bichlor., 1.35 gm.; Acidi acetici, 20 c.c.; Aq. destill. q. s. ut fiat 100 c.c.--Tauret's test. It may be used in the same way as the nitric acid or brine, or simply intermixed. Its only disadvantage is that it throws down alkaloids, but as this will not happen unless the alkaloid be taken in large quantity--as might happen, for instance, in the case of quinine--the chances of error from this source are not very great if this peculiarity be borne in mind. Ferrocyanide of potassium in an acid solution has recently been proposed as a convenient test. It may be made up into pellets with citric acid or used in the same combination in the form of papers. The phenic-acid test is prepared as follows: Ac. phenic. glacial. (95 per cent.), drachm ij; Ac. acet. puri., drachm vij; M. Add liq. potassæ, ounce ij-drachm vj. Millard. This is said to be very delicate, but the writer has no experience with it. Tungstate of sodium is another recent addition to the list, which it is evident is already long enough for practical purposes. Several of the tests mentioned have recently been prepared in the form of papers saturated with known quantities of the reagent and dried. They may be carried in the pocket-book and applied at the bedside, if desired, in a test-tube small enough to be very conveniently carried in the vest pocket. The iodo-hydrargyrate is perhaps the most useful. It is the most delicate, and a plan has been proposed for making with it a quantitative estimate of considerable accuracy by means of a standard solution or piece of gray glass adjusted by such a solution, with which the precipitate produced can be compared as to its opacity. Exact quantitative examinations for albumen may be made by several processes, but that by boiling, if carried out with the precautions described in works on chemistry, is as accurate as any, and probably the best adapted to the needs of the practitioner if he should wish for such results. For clinical purposes, however, it will rarely if ever be found useful to determine the amount of albumen more accurately than can be done by the various approximations mentioned above. When even the smallest trace of albumen is discoverable by any of these methods, the question of the integrity of the kidneys at once arises--a question which a few years ago would have been considered as settled in the unfavorable sense by the same occurrence.