It is often desirable that the percentage of albumen present should be determined at frequent intervals, in order to note the success or otherwise of the physician’s treatment.  These quantitative determinations, being intended only for comparative purposes, do not demand any very excessive degree of accuracy, such as would be difficult to obtain in ordinary practice.  The recent method of a Continental worker.  Dr. Esbach, affords indications sufficiently precise for therapeutical requirements, and is at the same time extremely easy of application.  The filtered acid urine is poured into the glass tube up to the mark U, and then the special reagent is added till the level of the liquid stands at R.

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Mix the liquids thoroughly, without shaking, by reversing the tube a dozen times, close with a cork, and allow it to stand upright for twenty-four hours.  The height at which the coagulum then stands, read off on the scale, will indicate the number of parts per thousand, or grammes of albumen in one liter.  This divided by ten gives the percentage.  Dr. Esbach’s test solution is prepared by dissolving 10 grammes of picric acid and 20 grammes of citric acid in 900 c.c. of boiling distilled water, and then adding, when cold, sufficient water to yield 1 liter.  The citric acid is only employed for the purpose of maintaining the acidity of the liquid, and is really not essential.

URIC OR LITHIC ACID.

The determination of the proportion of uric acid in urine was formerly rather neglected by physicians.  There is now, however, a growing tendency in a certain class of diseases to attach considerable importance to its accurate estimation, and, as some little trouble is involved, pharmacists should be prepared to undertake the work.  A rough way is to concentrate somewhat, acidulate with hydrochloric acid, and collect and weigh the precipitate thrown down on standing.  There are several objections, however, to this method, and many attempts have been made to elaborate a more reliable process.  One of the most recent, and which has been pronounced the most practical and successful, has been devised by Professor Haycraft.  Although apparently rather detailed and elaborate, the determination is easy and extremely simple.

The following solutions must be prepared:  1.  Dissolve 5 grammes of nitrate of silver in 100 c.c. of distilled water, and add ammonia until the precipitate first formed redissolves. 2.  Dilute strong nitric acid with about two volumes of distilled water; boil, to destroy the lower oxides of nitrogen, and preserve in the dark. 3.  Dissolve about 8 grammes of ammonic thiocyanate (sulphocyanide) crystals in a liter of water, and adjust to decinormal argentic nitrate solution, by diluting till one volume is exactly equal to a volume of the latter.  Dilute the solution thus prepared with nine volumes of distilled water, and label “Centinormal ammonic-thiocyanate solution.”