The relief or cure of cutaneous affections is effected in part by drugs and in part by other agencies; but, as drugs are by far the most important of the means at our command, special attention is here devoted to them. The systems of classification adopted by works on general materia medica were found inapplicable to the present purpose, and consequently an alphabetical arrangement was adopted, in the belief that it would, on the whole, prove more convenient and satisfactory. The drugs included are those which, according to the statements of authors, exert an effect (direct or indirect) on the skin, and it was the desire of the writer to present as full a catalogue of drugs, and as full a statement of observed effects, as his opportunities and the time at his disposal would permit. To this end he has carefully examined upwards of fifty treatises on materia medica, and an equal Dumber of works on dermatology, and less completely the files of about one hundred medical periodicals, transactions, etc. The result was the collection of a large mass of information which could only be rendered easy of access and readily available by some systematic plan of arrangement. The one adopted is as follows: If the drug is contained in the United States Pharmacopoeia, its officinal name is given; and if the drug be of vegetable origin, the name of the plant follows (in brackets) together with the botanical authority for the name, expressed in the usual manner. This is followed by an initial letter indicating the pharmacopoeia which includes the drug; and if it be not included in either the United States or British pharmacopoeias, by initials indicating the dispensatory in which a further account may be found.

In some oases one or more of these items fail, for the reason that the drug is not mentioned in any of the pharmacopoeias or dispensatories consulted.

The abbreviations indicating these works are as follows:

U.S........The Pharmacopoeia of the United States of America, 5th Revision.

B ......... British Pharmacopoeia, 1867.

G......Pharmacopoea Germanica, 1872.

F........ Codex Medicamentarius, Pharmacopee Francaise, 1866.

P.......... Pharmacopoea Homoeopathica Polyglotta, 1880.

U.S.D.....The Dispensatory of the United States of America.

N.D.......The National Dispensatory.

Following the title line, the drug is considered under four general heads indicated by the letters A, B, C, and D.

Under A, are embraced the effects on the healthy skin that follow the ingestion of the drug.

Under B, the effects produced on the healthy skin by the local application of the drug.

Under C, the cutaneous affections in which the drug has been found curative or useful when administered internally.

And under D, those in which the drug has proven useful when locally applied. In many instances one or more of these general heads is omitted for the reason that the author is not in possession of any facts or statements that could be properly included.

In certain instances, when the statements concerning the effects of ■ certain drug are well-known facts, as that mercury is useful in syphilis, no authority for the statement is given; in other cases the authority is indicated, and in many cases a number of authorities are given. Whenever practicable the exact words of the original, or their equivalent, are given. In some cases this is abbreviated to a single word, which performs the role of a predicate, the subject being the drug under consideration; thus, Under Arsenici Iodidum: C - Lupus, 44, 116; 83, 310 implies that the drug mentioned has been found useful, when internally administered, in the treatment of lupus. The heavy figures indicate the works in which this statement is made, and the smaller figures the pages on which it occurs. On consulting the bibliography, the numbers above given are found to correspond to Waring's Therapeutics, and to Thomson and Parkes'

Treatise on diseases of the skin. In references like the above, it is to be understood that I have personally examined the original; but a bracketed reference, e. g., (Henke's Zeitschrift, '21) 39, 76 implies that the original (in brackets) has not been accessible, and that the statement is taken at second hand, on the authority of the succeeding reference.

The words "dartres" and "Flechtenn will be found invariably in italics for the reason that they are words from foreign languages, and are of rather indefinite meaning and incapable of exact translation, unless the English word "salt-rheum" be accepted as their equivalent. The word scabies will also be sometimes met with in italics chiefly in references dating back to the last century, at which time the term had a wider significance than at present, and included the different varieties of eczema, lichen, etc., - in fact, was nearly equivalent to the French and German words above given.

With these explanations it is believed that the reader will be able to avail himself to the fullest extent of the practical information contained in this section of the book.

Until within a very few years there was hardly a drug credited with direct action on the skin, except arsenic and the various diaphoretics. The treatises on materia medica were silent on the subject, and even the more recent ones barely refer to the matter in connection with belladonna, bromide of potassium, and quinine. It is true that, with the exception of a very few drugs, the phenomena recorded under A are rare and unusual, and it is this very fact that makes it important that they should be collected together in some available form, for reference, if for no other purpose. The accomplished physician is supposed to have always in mind the more prominent and constant effects of the drugs he uses; these, his own experience as well as the teachings of the books have made familiar to him, but now and again, during the treatment of some common affection, unexpected symptoms referable to the skin may appear. Under these circumstances it will certainly be wise to consider the drugs he has been using, and to ascertain, if possible, whether similar effects have arisen at the hands of others, or, as Farquharson (116,179, 268) expresses it: "We, as practitioners, are bound to know all the irregular and abnormal effects of our remedial agents; and whenever we find the sudden appearance of some skin eruption which we cannot readily explain by the usual derma-tological reasoning, or even when a more chronic affection is difficult to explain on other grounds, let us never forget carefully to inquire what medicines our patient has been taking." More than once a medicinal rash has been mistaken for an idiopathic affection of the skin, and the unsuspected cause permitted to remain in operation.

Thus far dermatology has mainly considered the symptomatology and pathology of cutaneous affections springing from what might be termed natural, though frequently obscure, causes. The facts contained in the follwing pages, however, show us that there is great need of careful observation of an entirely different class of oases: those which arise through the agency of means intended to combat disease, but which in turn may become the originators of morbid action. On this point Farquharson (l. c. 223) says: "A large mass of evidence from many authentic sources, as well as the results of our own individual experience, must have convinced us that certain aspects of cutaneous irritation follow the administration of particular drugs with sufficient regularity and definition of form to stand in the relation of cause and effect." While it is true that in very many cases these effects are unusual, and are commonly explained as due to some idiosyncrasy on the part of the patient, it is none the less important that they should be recognized at the time of their occurrence, and assigned to their true cause.

They are facts with which we as intelligent physicians should be acquainted, as a portion of our science, even if they do not appear to possess an immediate or frequent application in the practice of our art.

The connection and relationship between the so-called physiological action of drugs and their therapeutic employment, is a question that of late years has assumed considerable importance, and one that in the near future will probably invite still more thorough investigation. At present, the well-ascertained facts bearing on these points are too few in number to warrant any general induction that can be extensively utilized in practice. We know, for instance, that arsenic, which during the past fifty years has been more extensively used in the treatment of skin diseases than almost any other drug, is credited by many competent observers with the power of also causing cutaneous eruptions. Iodide of potassium, likewise an exanthematogenic drug, is found useful in certain cutaneous lesions, and especially in those of a syphilitic nature. On the other hand, bromide of potassium and the cinchona derivatives, which exert a marked influence on the skin in health, have as yet received little attention as therapeutic agents in the treatment of idiopathic diseases of this organ. How far those drugs which display a predilection for the cutaneous tissues can be made to subtend a useful purpose in this connection, is a question that can only be settled by experimentation. It is a field of research, however, that should not be neglected, and all facts that may be ascertained should be placed on permanent record, as our successors may perhaps be able to utilize them, even if we are not prepared to do so to the fullest extent ourselves.

Under the headings 0 and D many statements will be found recorded in what may appear to the reader too brief a manner, with too little detail, especially as to the manner in which the drugs have been or are to be employed. In the case of the more important articles of the materia medica, this deficiency is supplied in Part II., in connection with the diseases in which they are found useful. In regard to the others, it was thought better to simply indicate the original sources of information, thus saving space for matters of more practical importance.

Under the heading Remarks, the preparations officinal in the United States Pharmacopoeia are given, and in addition, such other information as appeared to the author desirable to incorporate in this place. It should be remembered that all of the drugs mentioned in the United States and British Pharmacopoeia, and many others in addition, are more or less fully considered is the United States and National Dispensatories; and in these works of reference, one or the other of which is in the hands of almost every physician, will be found the effects of the drugs on other parts of the body than the skin - effects that should always be borne in mind when making use of the drug in question for therapeutic purposes, as they may sometimes serve as contra-indications to the cutaneous applications of the drug in particular cases.