QUERIES

Information is given in this department under the following conditions only: (1) No queries are answered by mail; (2) queries must reach us before the 15th of the month to be answered in the BULLETIN of the month following: (3) inquirers must in every instance be regular subscribers; and (4) names and addresses must be affixed to all communications.

To Filter Tragacanth and Quince Seed Toilet Creams. J. & L. ask: "Do you know of a quick and efficient method for filtering toilet cream made from tragacanth or quince seed?"

Undesired matter in quince seed or tragacanth toilet creams is best removed by straining the liquid through filter bags of flannel or felt; the liquid passes rapidly through the bag, all solid matter being effectually retained on the filter. Such a filter bag may be made by folding a square piece of cloth into a conical shape, sewing up the seam formed where the edges of the cloth overlap, and then suspending the bag in a square or round frame. The bag should be fastened to the frame by means of loops attached to the corners, if the frame is a square one, or to four equally distant points if a round frame is used. The liquid to be strained is poured into the previously-wetted bag, filtration proceeding more or less briskly according to the viscosity of the liquid.

In filtration as ordinarily carried out, the only pressure exerted is that due to the liquid itself resting on the filtering medium; but by increasing the height of the column of liquid the pressure is increased, and filtration is consequently accelerated. One of the principles of hydrostatics is that the thrust exerted by a liquid of given depth on the base of the containing vessel is independent of the shape of the remaining portion of the vessel, hence the column of liquid need not be of equal diameter throughout in order to produce uniform pressure. Acting on this principle, a simple means of filtering viscid liquids has been suggested. A filter bag is firmly attached to the lower end of a long tube, while to the upper end of the tube is fixed a funnel, into which is poured the liquid that is required to be filtered. Under such conditions the pressure exerted is that due to the weight corresponding to the total height of the column of liquid, and the filtrate is forced through the bag and collected. Instead of a filter bag an ordinary inverted funnel may be used; the filtering medium is tied securely over the broad mouth of the funnel, it being necessary always to support the filter paper between layers of cheese-cloth.

A vertical partitión fitted in a funnel to divide it in two parts will increase the filtering space 65 per cent. The partition is triangular-shaped, may be of tin or glass, and each compartment requires a sheet of filter

paper.

Filtering paper that is torn or that cannot be used in the regular way may be utilized by soaking to a pulp, washing, and stirring until the pulp is suspended

through the water. Pouring this on cheese-cloth tacked on a frame and spreading evenly will give a medium that is almost equal to a pressure filter in efficiency for filtering liquids or for rapid work. The pulp may be washed and used repeatedly.

Passing the tragacanth mixture through a sieve or flour sifter is also a method that is sometimes used for removing solid particles.

Preparation for a Board Examination.

H. B. asks: "Will you please inform me as to the titles, prices, and publishers of books that will be of assistance to a student preparing to take a State board examination?"

There are several books on the market which are intended to be of aid to students preparing for board examinations. Such books, if worthy of recommendation, almost invariably presuppose that the student has had an adequate training in pharmacy, and they are designed simply to familiarize him with the kind of questions likely to be asked.

"Board Questions Answered," published by E. G. Swift, P. O. Box 484, Detroit, Mich., is particularly valuable to the candidate who desires to "freshen up." It contains complete sets of examination papers actually used by the boards of pharmacy in the leading States, and answers to all questions are given with care and thoroughness.

Every one of the examination papers is complete in itself, and every last question asked by the board on the occasion represented is printed and answered; not even catch questions are dodged. The price of the book is $1.50, post-paid.

"Whys in Pharmacy," by E. A. Ruddiman, Ph.M., M.D., is described by the author as "a compilation of reasons underlying the principles of pharmacy." Questions and answers on pharmaceutical matters are printed, and the object of the book is to enable the student to grasp more fully the reasons for many pharmaceutical processes. "Whys in Pharmacy" is published by John Wiley & Sons, New York City, and the company will send you a copy upon receipt of one dollar.

"Students' Handbook of Pharmacy" is a third book that is used to some extent by students preparing for a board examination. It contains questions and answers in pharmacy, materia medica and chemistry. Marvin E. Pate, Dept. H, Madisonville, Ky., sells the book for 50 cents a copy.

Alcohol and Glycerin Antifreeze Mixture.

M. B. H. asks: "What information can you give me concerning the use of alcohol and glycerin to prevent freezing in automobile radiators?"

We quote the following from Studebaker Service, a collection of service helps for owners of Studebaker automobiles:

"Possibly one of the most important points in the care of your car that needs attention at this time of the year is the filling of the radiator with antifreeze. It is well to anticipate an unexpected drop in temperature and to provide material for the mixing of a suitable antifreeze mixture to be used in the circulating system.

"It is very possible that due to the advanced price of glycerin many owners will desist from using this ingredient, and in this case the percentage of glycerin rot used should be replaced with alcohol. For example: A solution calling for 6 per cent alcohol, 4 per cent glycerin, and 90 per cent water will become 10 per cent alcohol and 90 per cent water.

"The advantages of the alcohol are that it can be very easily handled, has no corroding action on the parts of the cooling system, and either wood or denatured alcohol can be used. The advantage of wood alcohol over denatured is that it has a lower boiling point and, therefore, less is required.

"The object of the glycerin is to retard the evaporation of the alcohol which will automatically take place. One point that must be brought to the owner's attention is this evaporation of the alcohol, which leaves a solution in the radiator containing a greater percentage of water than originally. This, therefore, requires that the owner occasionally add alcohol to the solution in the radiator to keep it at the original percentage."

Two bottle hair-dyes are put up in cases to hold a 1-ounce (No. 1) and a 2-ounce (No. 2), or proportionately larger bottles, with two short-handled toothbrushes of black and white bristles. The directions for use are as follows:

Cleanse the hair from all grease by washing it with warm water having a little washing-soda dissolved in it, and dry with a towel. Next pour a little of fluid No. 1 into a saucer and apply with the white-haired brush; immediately afterwards use No. 2 in the same

Mix and make a powder. Send 8 such. Directions: One in a quart of water and use as directed each night.

In prescription No. 1 the precipitate is probably due to the formation of zinc oleate. Creolin contains a considerable amount of soap in solution, from which the soluble oleates would be precipitated as zinc oleate. The physician should be advised that if he desires a uniform mixture it will be necessary to omit either the creolin or the zinc sulphocarbolate.

Prescription No. 2 is a safe one to compound, provided the permanganate and acid are not rubbed together.

Therapeutically, of course, the solution formed is practically worthless; a point which the doctor doubtless overlooked when he ordered the combination. Potassium permanganate oxidizes tannic acid.

A Prescription that Does Stunts.

H. W. writes: "One of our stores has tried, without success, to make a presentable mixture from the following:

Directions: Use as mouth-wash or gargle.

"When compounded the mixture liberates free iodine, evolves gas, and does other stunts. How can we proceed to make a stable and uniform mixture?" It can't be done. The mixture is an incompatible

one.

Hydrogen peroxide oxidizes potassium iodide, with the consequent liberation of free iodine and oxygen. In addition, the menthol and camphor liquefy when brought in contact, and the resulting liquid is insoluble in the remainder of the mixture.

Dissolve separately each of the salts in one pint of water. Then mix the solutions and apply the mixture, heated, to the gun barrels. The surface of the barrel should have been previously entirely freed from oil and grease by wiping the surface with a solution of potassium hydroxide. When the blue color has developed, wipe the barrel dry and polish it with oil.

Before applying the liquid it is advisable to insert a cork stopper in the end of the barrel in order to prevent any of the fluid from getting inside.

Serial Numbers No Longer Required.

H. E. D. asks: "To whom shall I write in order to obtain a serial number? I would also like to know where to secure information regarding the registry of a trade-mark."

It is not necessary at all, under the Federal Food and Drugs act, to guarantee any of your preparations. When a manufacturer does guarantee a product it is merely for the purpose of satisfying his distributers, protecting them against legal trouble, and thus earning their good-will. If you decide to guarantee a product, however, you can no longer get a serial number issued

Who Makes "Mentholated Tar Ointment?"

T. J. H. writes: "I am desirous of obtaining a supply of a preparation marketed under the name of 'Mentholated Tar Ointment.' I have tried in every conceivable way to locate the manufacturer, but so far I have been unsuccessful. Can you help me out?"

"Mentholated Tar Ointment" is not listed in any of the catalogues which we have at hand. It may be, however, that some of our readers are familiar with the product. We are, therefore, issuing an appeal for help in the hope that some one will furnish the necessary information.

Will some member of the BULLETIN family send us the manufacturer's address so that we, in turn, may pass it along to T. J. H.?

Mix thoroughly by agitation. Two ounces of Kieselguhr may be used in place of the ferric oxide, and crystal white petroleum oil may be substituted for the Putz oil.

You will find a formula for an automobile polish containing liquid paraffin in the department of "Business Hints" elsewhere in this issue.

M. J. W.-We are not familiar with the composition of the proprietary preparation you mention