GENERAL PRINCIPLES AND RULES

Before taking up the individual drugs some general definitions should be discussed and some generalizations concerning the collec- tion and preservation of drugs should be given consideration.

The natural origin is the scientific name (generic and specific names) of the plant or animal yielding the drug. In the case of vegetable drugs the natural origin is spoken of as the botanical origin.

A vegetable drug usually represents some special part of the plant, but in some instances the entire plant is employed as chirata.

The habitat of plants is the region where they grow. Sometimes this term is applied erroneously to the drugs themselves. Neither the scientific name of the plant nor the commercial name of the drug may be relied upon as indicating the true habitat of medicinal plants. For example, the specific name of Spigelia marilandica indicates that the plant is found in greatest abundance in Maryland, whereas it is only occasionally met with in that state. In other cases plants are common to a much larger territory than the specific name would indicate, as Prunus virginiana. The geographical names associated with drugs frequently apply to the places from which they are exported rather than to the habitat of the plant yielding the drug, as, for example, Para sarsaparilla, which is obtained from a plant growing in the upper Amazon region, is shipped to Para, from whence it was formerly exported.

Plants which yield drugs may grow wild, as is most usually the case, or they may be cultivated, as those yielding digitalis, cannabis indica and the solanaceous leaves. Plants growing in their native countries are said to be indigenous to those regions,

as Stillingia sylvatica, of the Southern United States; Aconitum Napellus, of the mountainous regions of Europe, etc. Plants are said to be naturalized when they grow in a foreign land or in another locality than their native home. Some of these may have been distributed by natural agencies, or they may have escaped from cultivation, or they may have been introduced with the seeds of cultivated plants or with the ballast of ships.

The term commercial origin applies solely to the drugs themselves, and indicates their commercial source, which may be either the country where the plant yielding the drug is grown, or the port from which the drug is sent into the marts of the world. English hyoscyamus leaves are gathered from plants grown in England; Canton rhubarb is the product of plants grown in various parts of China, but shipped by way of Canton.

The official or pharmacopoeial titles of vegetable drugs are derived from either the generic name of the plant, as gelsemium, or the specific name, as ipecacuanha, or they may include both the generic and specific names, as viburnum prunifolium, or they may be derived from other sources, as opium and sarsaparilla.

In addition to the botanical names of plants and the pharmacopceial titles of drugs, a number of vernacular names and synonyms are also applied to vegetable drugs, as licorice root for glycrrhiza, prickly ash for xanthoxylum.

The official or pharmacopoeial definition of drugs is given in the leading paragraph under each drug in the different pharmacopoeias, and includes the botanical origin as well as the name of the part of the plant yielding the drug; and in some cases other special features or requirements are given, as the habitat of the plant yielding the drug, the time of collection, mode of preservation, etc.

The time of the collection of vegetable drugs is of prime importance, and, while we may not be able to make extended generalizations, still, the following general rules for the collection of various drugs may be given :

(1) Roots, rhizomes and barks should be collected immedi- ately before the vegetative processes begin in the spring, or imme- diately after these processes cease, which is usually in the fall.

(2) Leaves should be collected when photosynthesis is most active, which is usually about the time of the development of the flowers and before the maturing of fruit and seed.

(3) Flowers should be collected prior to or just about the time of pollination.

(4) Fruits should be collected near the ripening period, i.e., when full grown but unripe.

(5) Seeds should be collected when fully matured.

The preservation of vegetable drugs is likewise deserving of careful consideration, and attention should be given to the influence of temperature, moisture, air and light, and the attacks of insects.

The temperature of the room or part of the store devoted to the storage of dry drugs should not be more than about 25 C., and maintained nearly uniform throughout the year.

Drugs containing volatile principles require to be kept in air-tight containers, as the herbs of the Labiatse and Composite, and wild-cherry bark. Air-tight tin cans are probably the most eco- nomical and satisfactory containers for the purpose, and the suggestion has been made to coat the edges of the cans with melted paraffin. Drugs are sometimes stored in wooden boxes or in drawers. This method is objectionable, not only because they are more liable to deteriorate, but because the odors are communicable from one to the other. The storage of drugs in parcels is the most objectionable, particularly, as is usually the case, when the different parcels are stored together.

Those drugs that are difficult to dry, as the inulin-containing drugs, and some fleshy roots and rhizomes, as Veratrum, are liable to become moldy and should be thoroughly dried before placing them permanently in containers.

The preservation of drugs against the attacks of insects is, unfortunately, generally overlooked. Most drugs are subject to their depredations, and are usually attacked by the insects in the larval stage. The insects which infest vegetable drugs belong chiefly to the Lepidoptera, Coleoptera and Diptera. The Lepidoptera are the most destructive, and include the cornmeal moth (Tinea zea), which, during its larval (the caterpillar or grub) stage, is known to attack aconite, capsicum, ergot, lappa, linseed, rhubarb, taraxacum and many other drugs. Among the Coleoptera are various members of the Ptinedse, as Ptinus brunneus, Anobium paniceum and Lasioderma serricorne, which attack the spices chiefly, as capsicum, cin- namonandpimenta. ChiefamongtheDipteraisTrypetaarnicivora, which is sometimes found in the receptacles of arnica flowers.

For the destruction of these insects and prevention of their attacks a number of substances and methods have been employed, the simplest method of all being to expose the drug to a temperature of about 65 C. This method is probably the most efficient in not only preventinginsectattacks, butallo their forms of deterioration. Camphor and tar-camphor have been employed, but it is doubtful if they should be used, unless in the case of animal drugs. In some instances, as with nutmeg and ginger, the drug is sprinkled in the drying-room, or when packed for market, with quicklime. Benzin and carbon disulphide have been proposed, but these are of a disagreeable odor as well as inflammable. Ether has been suggested, but it is very volatile and inflammable. Formaldehyde has been proposed for the preservation of orris root. Chloroform and carbon tetrachloride are probably the best preservatives that have been proposed. A few drops of chloroform or carbon tetrachloride added to a drug on placing it in the container will usually prevent it from becoming

The amount of chloroform or carbon tetrachloride to be used should be about 25 c.c. to 100 cubic feet of drug. To be effective the drug should be treated on two separate occasions.

Commerical Forms of Drugs. Vegetable drugs are brought into market in various forms; they may be crude; that is, more or less entire, or in a powdered condition. Crude drugs may be nearly entire, as seeds, flowers, fruits, leaves, and some roots and rhizomes; or they may be cut or sliced, as in woods, barks, many roots and a few rhizomes. Theymaybemoreorlessmattedtogether, as inchondrus and the solanaceous leaves; or they may be pressed together by means of hydraulic pressure, giving the so-called pressed drugs;""wormy." or they are first powdered and then molded into forms, as rhubarb fingers." In some cases the periderm is removed, as in roots (althea) , rhizomes (zingiber) and barks (ulmus).

The quality of vegetable drugs is injured by a number of factors, of which the following may be mentioned: (1) Lack of knowledge or want of care in collecting them; (2) carelessness in drying and keeping them; (3) insufficient care in garbling and preparing them for the market; (4) inattention in preserving them and storing them; (5) accidental admixture in the store, and (6) adulteration and substitution.

The influence which the time of collection has on the quality of vegetable drugs may be best shown by a few illustrations. It is well known that when the fruits of conium are green they will yield over 3 per cent of coniine, but when they become yellow the alkaloid diminishes rapidly in quantity, and, therefore, much of the commercial drug will not yield 1 per cent of coniine. The same thing may be said of santonica; when the flower heads are unexpanded they will yield over 3 per cent of santonin, but just so soon as the flowers mature there is a rapid disappearance of the anthelmintic principle. Dealers in insect powder (Pyrethri Flores) know that the flowers gathered when they are closed produce the finest and most powerful insect powder, worth nearly twice as much as that made from the half-closed or open flowers. It may be that the variation in quality of some of the commercial aconite is due to improper drying, or to the extraction of the active principles; still, there is no doubt but that much of the trouble with this drug is due to the variation in the time of collection in different countries, as well as to its being collected from different species.

Another factor affecting the quality of vegetable drugs is carelessness in drying them and caring for them after they are gathered. At one time the Pharmacopoeia specified that some drugs should be kept a certain length of time before being used, as in frangula and cascara sagrada. In these instances the results of the changes on keeping have been ascertained, and since a similar effect may be obtained by heating the barkat 100 C. forforty-eighthours, this specification is deemed no longer necessary.

In some drugs a sort of ripening process takes place in the drying, as in gentian, guarana, vanilla and the solanaceous leaf drugs. In still others a marked deterioration takes place if they are placed in heaps and allowed to ferment, as in the case of lavender and most other drugs yielding essential oils. In the preparation of oil of peppermint, the yield of oil is greater and the quality better if the plants are allowed to dry and are distilled immediately of soon after. On the other hand, the yield of methyl salicylate is greater in the leaves of Gaultheria procumbens or the bark of Betula lenta if they are first macerated in water for about twelve hours.

Quite a number of drugs are not infrequently observed in commerce in a moldy condition, as taraxacum, veratrum, aconitum, zingiber and others. The question as to what influence this mold has on the quality of the drug has not been decided. 1

A third cause of inferiority of vegetable drugs is lack of sufficient care in garbling. This applies to a number of drugs, as leaves, with which may be admixed a large number of stems and roots; rhizomes and tubers, in which the proportion of stem-remnants may be excessive, or, as in other cases, the proportion of roots to rhizomes may be large. The roots contain much less of the active principles, and have been found in cypripedium and hydrastis to the extent of 50 per cent of the amount present in the rhizomes.

A fourth factor influencing the quality of drugs is the manner of preservation. While it is generally conceded that most drugs deteriorate on keeping, still this depends largely upon the manner in which they are kept. Thus, the Pharmacopoeia limits the time of keeping of ergot and states how it shall be preserved ; yet a number of writers call attention to the fact that, if properly prepared and preserved, the time of keepingmaybeverymuchextended. Inorder to preserve ergot, Grover proposed the removal of the oil, and Moss found the drug thus treated to retain its therapeutic value for six and a half years. Zanon suggests placing the drug in alternate layers with sand and keeping it in a closely sealed jar. Others grind the fresh ergot and preserve with chloroform in paraffin paper, while some first extract the oil from the powder with alcohol or ether.

Accidental admixture in the store or warehouse depends upon the care of the individual, and need not receive attention here.

The Valuation of Drugs. In the identification of vegetable dfligs certain characters are taken into account, such as color, odor, general appearance, structure, texture, etc., these at the same time indicating inagreaterorless degree the qualitative value of the drug. While these characters may enable the expert to detect very slight variations in quality, and to estimate approximately the value of a given drug, still the true value is based upon the amount of the medicinal principles or so-called active constituents. The methods employed in the valuation of drugs may be grouped as follows: (1) Chemical, (2) Physical, (3) Microscopical, and (4) Biological.

(1) Chemical methods are more generally employed and usually involve the isolation and estimation of the active principles.

(2) Physical methods involve such processes as the determination of specific gravity of the drug as of jalap, or the determination of the elasticity or measurement of the fibers, as of cotton, and still other special methods which apply to individual drugs, showing indirectly their quality.

(3) Microscopical methods of valuation may oftentimes be employed when other methods fail, as, for example, when foreign starches are added to starchy products, as the cereals and spices. Microchemical reactions may also be depended upon in some instances to indicate the value of a drug, as in strophanthus, where the quality of the drug appears to bear a direct relation to the number of seeds giving a green coloration with sulphuric acid. The separation of the salts of the alkaloids in hydrastis on the addition of sulphuric acid is also of value in determining the quality of this drug.

(4) Biological methods involve the consideration of the effects of drugs upon animals or plants. They may be conveniently grouped as follows: 1. Effects or influence upon animals, including (a) those dependent upon the perceptions or senses of the experimenter or tester, as color, taste and odor; (6) those which are physiological or pathological. These are usually determined by experiments upon insects, frogs, rabbits, guinea pigs, fowls, cats, dogs, fish and even uponman. 2. The effector influence produced upon plants by drugs, or solutions of their active principles. For experiments of this kind seedlings are usually employed and the effects are based upon the amount of growth of the root of the plant in a given time when placed in the solution.1 Some of the lower are also used in testing the properties of chemicals, which may have a toxic action on the protoplast or a plasmolytic action on the protoplasm.

Drug Collections. It is important that the student, pharmacist and analyst possess a collection of typical drug specimens. It is necessary in the study of drugs and also for purposes of identification and comparison. Specimens may be kept invarious kinds of boxes and bottles, but one of the most satisfactory ways is to keep them in type cases, such as are used by printers, the top being covered with glass which can be removed. The glass can be kept in place by means of long, broad-headed tacks or can be fastened permanently by means of hinges. The frames may be hung on the wall or held by means of molding.

The Study of Drugs may be pursued from a number of viewpoints.

In an artificial system they may be grouped according to the parts of plants from which they are derived, as roots, rhizomes, leaves, etc. This method has much to commend it in practice, but unfortunately the form of the commercial article is not such that it is always pos sible to determine whether it should be placed among roots or rhizomes, leaves or herbs, etc. A second system of arranging drugs is according to their important constituents. This may seem to many very desirable and enable us to develop a scientific pharmacognosy to be used as a basis for a rational pharmacology. Unfortunately our knowledge of the chemical constituents of drugs is very meager, and in those drugs which have been investigated there may be present a number of principles, each one of which serves a useful purpose. A third method is to consider the plants yielding drugs according to their natural relationship. With our knowledge of the morphology, including both organography and the inner structure of such a large number of plants, it would seem that this would furnish the best system for practical pharmacognosy and be the most stimulating to the investigator. In a large number of families we find there are certain morphological characters that are more or less distinctive for each. The Composite, for instance, are distinguished by their containing inulin. The Labiatae have not only square stems and bilabiate calyces and corollas, but typical 8-celled glandular hairs. Furthermore, two or more drugs are not infrequently derived from a single plant, and the reason for this can be better considered in connection with the products derived from a single plant than if they are placed in widely divergent groups. After many years of experience as a teacher and trying out the several methods in class work I have come to the conclusion that the natural classification of plants is not only the most systematic, but the most effective in practice.

Literature. Tschirch, Handbuch der Pharmakognosie, 1912.

Power, The Aims and Developments of Phytochemical Research. Am. Jour. Pharm., 1917, 89, p. 97.

Lloyd, Plant Textures, Amer. Jour. Pharm., 1917, 89, p. 387. EwingandStanford,BotanicalsoftheBlueRidge. Jour.A.Ph.A., 1919, 1 p. 169.

Taylor, The Pharmaceutical Chemist and the Scope of his Work.

Jour. Indus. Eng Chem., 1919, 11, p. 239. Alsberg,ViehoeverandEwing. Some of the Effects of the War upon Crude Drug Importations. Jour.A.Ph.A.,1919,8,p.459. Beal, George D., Chemistry's Opportunity in Pharmaceutical Research. Jour. A. Ph. A., 1919, 8, p. 260.

Kebler,FraudulentAdvertising. Jour.A.Ph.A.,1919,8,p.201. Power. The Distribution and Characters of some of the odorous

Principles of Plants. Jour. Indus. Eng. Chem., 1919, 11, p. 344.

Soure: Scientific and applied pharmagognosy by Henry Kraemer, New York, John Wiley & Sons, Inc. London: Chapman & Hall, Limited 1920