PART II THE MICROSCOPICAL CHARACTERISTICS OF THE VEGETABLE POWDERS In order that the student may take up the critical study of powdered vegetable drugs as to quality and purity, he must have the necessary preparation. Such preparation is given in the courses in general botany, in plant morphology and histology, and in pharmacognosy, as presented in the first and second years of the college curriculum. The significance of the adulteration of drugs has been explained in Part I. Throughout the examination of the powders listed in Part II, the student is urged to search for the foreign inclusions which may be present and to record these descriptively and by means of drawings. The first thing to be accomplished is to acquire the ability to recognize foreign inclusions, after which the special training must be directed along the following lines. 1. To recognize those inclusions which are wholly unavoidable. 2. The wholly negligible inclusions. 3. The usual or more or less normal sophistication and adulteration. 4. Conventional sophistication. 5. Unquestionable sophistication and adulteration. As to (1), the student will soon learn that all crude as well as powdered vegetable drugs contain some foreign substances, as dirt and sand particles, some bacteria, occasional spores and pollen grains, a trace of foreign vegetable tissue, occasional nematode or insect, remnants, etc. Even the gum tragacanth contains some starch; the highest grade cloves contains a small amount of stem tissue; the best quality black pepper contains some pepper refuse; the best chocolate and cocoa contains some shell tissue; and the purest coffee contains some coffee chaff. These are among the wholly unavoidable inclusions and which may not be considered as adulterants. As to (2), it is common knowledge among dealers in drugs and those who use drugs for manufacturing purposes, that certain more or less accidental and unavoidable inclusions are always to be found in crude as well as in powdered vegetable drugs, and which inclusions are generally considered so small in amount as to be wholly negligible. These inclusions usually consist of dirt, clay, foreign roots, leaves, stems, etc. It is also generally admitted that with greater care on the part of the growers and gatherers of drugs, these inclusions could be removed with the exception of the substances mentioned under (1); but the extra labor entailed and the consequent increase in the price, does not, by general agreement, warrant the removal of the wholly negligible inclusions, which rarely reach 5 per cent. (2) gradually merges into (3). It is common practice on the part of the careful wholesale pharmaceutical manufacturer, to open up the bales of crude drugs as they are received, spreading them out on a floor and to cull out foreign plants, roots, etc.; or to winnow out dust, dirt, foreign seeds, fruits, chaff, etc.; or to remove, by means of sieves, pebbles, defective or undersized specimens, etc. This more or less common normal or usual sophistication often amounts to 10 per cent. and may reach 20 per cent. in some instances. This type of sophistication or adulteration is generally due to carelessness in gathering and garbling for the market. This form of adulteration usually escapes the vigilance of the U. S. customs and the food and drug inspection, and even when detected the amount of adulteration is usually not considered sufficient to warrant entering upon condemnation procedures, and the dealer is informed that the article contained an excess of foreign matter and is advised to avoid future shipment of such inferior quality. Among the conventional adulterations may be mentioned the limeing of ginger and nutmeg, the coloring of tea and coffee, adding a trace of Prussian blue to beet sugar to increase its whiteness, adding caramel to bay rum, whiskey, brandy, etc., adding color to butter and cheese, etc. Some of these forms of adulteration are time honored and the reasons for their existence are generally not clearly understood. In some instances it is supposed to please the esthetic sense, but in the majority of instances the custom arose from a desire to hide or mask inferiority or poor quality. The conventional forms of adulteration are gradually being abandoned, or are made unlawful. Thus, it is no longer permissible to color tea or coffee in the United States. Prussian blue may no longer be added to sugar. The forms of actual and unquestioned adulterations were discussed in Part I. The student should be given adulterated samples and he should be required to determine the percentages of the adulterants according to the methods outlined in Part I. The student should be fully informed as to the importance of experience and good judgment in rendering a decision as to the degree and the kind of adulteration which has been perpetrated, always bearing in mind that the law is for the protection of the consumer but that the dealer also has his rights and privileges under the same law. These are matters which must be left to a competent and experienced instructor for fuller explanation and discussion. In entering upon the special study of powdered vegetable drugs and spices, the student should be supplied with liberal samples of the pure article reduced to suitable fineness, usually No. 80. The necessary chemicals and reagents must be at hand; also a drug mill and a nest of sieves. The question is frequently asked, how many samples can a student examine in the time usually allotted to the laboratory course in the microanalysis of vegetable powders? The student who has the university entrance requirement (namely, graduation from an accredited high school or its educational equivalent) to the college of pharmacy, and who has had one year of botany in the college of pharmacy, plus the laboratory course in pharmacognosy, can readily examine from four to five powders during a laboratory period of two hours each; or, from fifty to seventy-five powders during the semester. The diligent student can, however, examine a far greater number of powders, though not all of them with the same degree of care or the same detail. He may examine from fifty to seventy-five carefully, including the making of drawings of the more important histological elements, and perhaps an equal additional number merely as to the microscopical characteristics, without making drawings. The descriptions are given in alphabetical sequence for convenience of study and cross reference. The drugs marked "U. S." are official in the pharmacopoeia of 1910 (made official September 1st, 1916). Upon comparing the U. S. P. IX with earlier editions, it will be found that many comparatively unimportant drugs have been dropped and the weeding out process will no doubt be continued for the good of all concerned. Most of the drawings were made to scale by means of the Abbé camera lucida. The more characteristic tissue elements are figured but no attempt has been made to indicate the relative abundance of the different tissues or cell contents figured. The following is the plan of the sequence of the special description of each powder; official name, common names, indication whether official or not, usual fineness of the powder, botanical origin and part used, color, odor, taste, histological characteristics, ash content, and more common adulterants. 1. (Fig. 1.) ABSINTHIUM. Absinthium. Fl. ex. 30. Tinct. 30.. Mugwort, Wormwood, E., Wermuth, Alsei, G., Absinthe commune, Grande absinthe, aluine, Fr. The leafy tops of Absinthium vulgare Lam., Compositæ. Grayish green. Faintly aromatic, disagreeable and narcotic when briskly rubbed. Very bitter, somewhat saline. The most distinctive tissue elements are the very abundant Tshaped, rather thin-walled trichomes with three to four basal cells; the rather large, yellowish, sessile, glandular trichomes with several vertical tiers of cells, are also quite diagnostic; some pollen grains presenting the characteristics of the pollen of the order Compositæ will generally be found. The vertical walls of the epidermal cells are wavy or sinuate and the stomata are abundant and fairly large. Compare with Achillea and insect powder which are similar in certain of the histological characteristics. Ash should not exceed 13 per cent. Related species may be used as adulterants or may be substituted for it, although this is of rare occurrence. |