water to soften or dissolve the lumps; the plates should then be quickly dried, to prevent rusting. By running sawdust or rice chaff through a mill, after an odorous drug has been ground, it may be speedily cleaned and freed from odor. Trituration is the process of reducing substances to fine particles by rubbing them in a mortar with a pestle. The pestle is given a circular motion, accompanied by downward pressure, and the most effective method of using the pestle is to begin in the centre of the mortar and describe a circle of small diameter with the pestle on the substance, and gradually increase the size of the circle with each revolution until the side of the mortar is touched, when the motion is reversed and circles continually smaller in diameter are described until the centre is reached : this is repeated until pulverization is effected: by this treatment all the particles are brought under the action of the pestle. The mortar and pestle best adapted for this operation have the shapes shown in Fig. 207. Mortars with pestles having flattened ends are the best. Wedgwood-ware is very serviceable, but is difficult to keep clean. As triturating mortars are rarely subjected to blows, porcelain mortars of proper shape are preferred. One of the principal annoyances in the use of wedgwood or porcelain mortars and pestles is that of the continual loosening of the handle of the pestle. The cement employed by the manufacturer is chiefly rosin of bad quality, and in using the pestle the particles of loosened cement often drop into the mixture in the mortar during trituration. The best plan is to pull the handle out of the pestle entirely as soon as possible and reset it: this is easily done by heating the end of the pestle in a sand-bath until the cement has softened so that the handle may be extracted, then some hot cement (good sealing-wax) is poured into the pestle-hole, and the wooden handle is at once pressed forcibly in and FIG. 207. FIG. 208. Mortar and pestle. Pestle (hard rubber handle). held in its place by wedging or other means until the sealing-wax has hardened. The hard-rubber handle, which is made to screw accurately into the pestle (see Fig. 208), is a great improvement over the ordinary handle, and the additional cost is more than repaid by the comfort of using it. Where trituration is combined with contusion, as frequently FIG. 209. happens in effecting solutions of chemical substances, a wedgwood mortar of the shape shown in Fig. 209 is well suited for the purpose. The selection of good mortars and pestles is frequently overlooked amidst the many items of detail in furnishing a pharmacy; but few implements bring more satisfaction to the operator than good mortars and pestles. It is a safe rule to examine every purchase carefully before accepting it finally, to see whether the pestle fits the mortar accurately: it should have as much bearing on the interior surface of the mortar as its size will permit, because the rapidity of the trituration depends largely on the amount of contact of the surfaces. The use of a round-surfaced pestle in a flat-surfaced mortar is just as great a waste of labor as that of a flat-surfaced pestle in a round-surfaced Wedgwood mortar and pestle. FIG. 210. mortar. Trituration, as a distinct method of preparing a class of preparations, was officially recognized in the U.S. Pharmacopoeia of 1880, and a new preparation, Trituratio Elaterini, made by triturating elaterin with sugar of milk, was introduced. Fig. 210 shows a device for facilitating trituration. It was communicated by Charles Rice, and is simpler and more effective than similar contrivances which have been described. It consists of an ordinary mortar and pestle, the latter having been lengthened by cutting down the mushroom top of the handle, so as to admit of its being inserted into the large end of a wooden handle, shaped somewhat like a ball-bat, and between two and three feet long. The upper end of this handle should be about an inch in diameter, and during the use of the pestle is to be kept upright and steady by passing through an opening in a piece of heavy pasteboard or wood which may be tacked to the under side of some convenient shelf. The mortar should stand on a counter about three feet from the floor, and the upper end of the pestle pass through a shelf above. To stop the noise caused by the pestle striking against the sides of the opening, a piece of sole-leather is attached to the under side of the shelf and the pestle passed through a hole in its centre. This also serves Triturating with another purpose; viz., when it is necessary to raise the pestle to admit of changing or stirring the contents of the mortar, the leather will clasp the enlargement of the handle so as to suspend the pestle securely out of the way of the hands. In using the apparatus, one hand grasps the handle just above its lower end, and a very slight effort is requisite to give it the necessary motion. The weight of the handle is usually sufficient to insure a proper degree of friction. If, however, more pressure is desired, the pestle can be weighted by slipping a perforated weight on to an iron pin driven in the top of the handle. not FIG. 211. Mortars and pestles are sometimes made of green or white glass. The former are to be preferred because they are stronger; the latter, however, present a handsomer appearance. Glass mortars are adapted to the continued trituration of hard substances. They are useful only in dissolving certain chemical substances directed in prescriptions, like corrosive sublimate, the alkaloids, etc. It is best to place the glass mortar over a dark surface, in order to show by contrast more clearly when the solution of the white object is effected. Porcelain mortars and pestles (see Fig. 211) are, however, more generally useful as solution mortars. Pestles entirely of porcelain are objectionable, because they are so easily broken. Porcelain mortar and pestle. Spatulas. The process of trituration as ordinarily performed requires the use of spatulas. These consist of flexible steel blades attached to handles, and in trituration they serve to loosen the substance as it becomes packed upon the sides of the mortar. Spatulas are largely used in extemporaneous pharmacy, and they will be alluded to frequently under various special heads in Part VII. The blade of a spatula is frequently broken when too much pressure is applied, but if the broken blade remaining in the handle have its sharp corners ground off upon a grindstone, or filed off, it will be just as useful for some purposes as it was when perfect. Spatulas may now be had of excellent quality, and greatly improved in style over those formerly used. The best form is the balance-handled spatula (see Fig. 213). In this the metal of the handle and that of the FIG. 212. FIG. 213. Balance-handled spatula. blade are continuous and of the same width, so that the annoyance of the tang becoming loose in the handle, as in the old-style spatulas, is avoided. The flat metal handle is enlarged by riveting smooth, flat pieces of hard wood to it to insure convenience in using. The balance-handle derives its name from the fact that when lying upon the counter the weight of the handle is sufficient to overcome the weight of the blade, so that contact of the blade with the counter is prevented. Solid-handled spatulas (see Fig. 214) are also made, the whole being of one solid piece FIG. 214. Solid-handled spatula. of metal, and the handle being nickel-plated. A pocket spatula, which closes like a clasp-knife, is also furnished by dealers. Fig. 215 shows a spatula coated with hard rubber, made by Fox, FIG. 215. Steel spatula blade, coated with hard rubber. Foultz & Webster, for making ointments which contain corrosive substances, or substances acting on steel. Sifting is the process of passing a powdered substance through the meshes of perforated material with the object of separating the coarser from the finer particles. Sieves are employed in this process: the frames are usually round, although sometimes they are oval, square, or rectangular. The ordinary sieve is usually made by stretching wire gauze over a flat wooden ring, and keeping it in its place by slipping over it a narrow wooden ring of slightly greater diameter, which is tacked securely. Covered sieves, or drum sieves, have tight covers for the top and bottom. The simplest pharmaceutical sieve for general use is obtained by making five rectangular frames, each four inches deep, ten inches wide, and sixteen inches long. These should be light but strong, and the bottoms covered with brass-wire gauze of different degrees of fineness. A box, ten inches deep, twelve inches wide, and twenty-two inches long, with a tight cover, is provided to hold the sieves and prevent dust from escaping. Two cleats are nailed horizontally upon the sides of the box, five inches from the top, for the sieve to slide upon, and a hole is cut in the front of the box in order to permit a handle, with a hook at the end, to pass through and be attached to a screw-eye in the front side of the sieve; two large corks are screwed to the back of the sieve at either end to act as buffers. The powdered substance is introduced into the proper sieve, which is placed upon the cleats, and the handle passed through the hole and hooked to the sieve; the cover is then placed in position, and the sieve pushed backward and forward, touching the back lightly. A very important point, which must not be omitted after sifting substances, is the thorough mixing of all portions of the sifted powder, in order that each part of the finished powder may have a uniform composition. The starchy portions of a drug will be powdered more quickly than the ligneous portions, and will usually pass through the sieve first: hence the sifted powder must always be thoroughly mixed. Upon the small scale this may be easily effected with a spatula or mortar and pestle; upon a larger scale special apparatus is needed. Hunter's sifter is one of the most effective: it is shown in Fig. 216. In this the powder is sifted in the cylindrical sieve, and adhering particles or small lumps are brushed through by the revolving brushes; the revolving spiral mixers in the large box cause the particles to be thoroughly mingled. The illustration shows the method of operating so well that further description is unnecessary. In Fig. 217 is seen an enclosed sifter well adapted for many purposes, whilst Fig. 218 shows a sectional view of the same kind of sifter for smaller operations. The sieve is hemispherical in shape, and is contained in a tinned-iron scoop (see Fig. 219, which shows the end view). Two circles of stout wire are soldered to a central axis at right angles to each other, and the axis passes through the tin handle and terminates in a crank. When a powder is placed in the scoop, and the wire rings are made to revolve by turning the axis with the hand, the particles of powder are |