The rapid exhaustion of the second edition of this work has prevented me from making as many improvements in the present edition as I could have desired. At the same time I have tried, as far as the short time at my disposal would allow, to amend the imperfections of former editions, as well as to bring the work up to date and render it more useful by the introduction of new matter.

The treatment of one of the most important portions of Pharmacology, viz. the Connection between Chemical Constitution and Physiological Action, is still very meagre, because I find that the size of this work would be too much increased were I to treat the subject fully, and I am therefore preparing a small text-book upon it.

The struggle for existence between microbes and the living organism, which in the first edition was only illustrated by a single diagram of a bacillus and amoeba, is now fully illustrated by woodcuts copied from Metschnikoff's paper. The views of Hughlings Jackson on the nervous system have been illustrated by a diagram which, when covered with successive layers of thin and semi-transparent paper, exhibits the effect of anaesthetics and narcotics in successively abolishing various faculties. The recent work of Kuhne and Politzer on the mode of action of curare has been noticed, and the pathology of tremor discussed. The section on the action of drugs upon the eye has been carefully revised. The section on antipyretics has been rendered somewhat fuller, and some diagrams illustrating the pathology of fever and the mode of action of antipyretics have been introduced; but it is very difficult in the present state of our knowledge to deal satisfactorily with this subject. Paragraphs on the treatment of cough and on the pathology and treatment of asthma have been introduced. The researches of Adami on diuretics have been noticed, but they have not necessitated any essential change in the text, as the communication between the portal vein of the kidney and the renal artery had been already allowed for in describing Nussbaum's researches in the first edition. The views expressed in the first edition regarding the mode of action of caffeine have been confirmed and extended by the observations of Schroeder and Munk. The researches of Jendrassik on the diuretic action of calomel and the explanation advanced by Locke have been noticed.

The arrangement of the Vegetable Materia Medica has been almost entirely remodelled on Hooker's plan, and a short introduction has been added to it, in which I have tried to show the use of botanical arrangement, as well as to protest against the abuse of it in the examination of students in Materia Medica.

By the use of small type for matters which are of practically little interest to general students, and yet are occasionally wanted for reference, a certain amount of space has been gained, at the same time that the general student is enabled at a glance to distinguish the parts which are of little or no interest to him. Notwithstanding my efforts to condense it, the present edition contains about 120 pages more than the second, but by using thinner paper the bulk of the volume has been little, if at all, increased.

The General Index has been carefully revised. The Index of Diseases and Remedies has been revised to a certain extent, but it still remains a mere skeleton of what it ought to be. It is little more than a list of drugs which have been recommended by somebody or other at some time or other in the treatment of certain diseases. In a few instances the conditions supposed to indicate the use of one drug in preference to another have been given, but I have not yet been able to sift the statements which have been made regarding the different drugs. The only use of the Index at present is simply to remind the practitioner who is treating a disease of the names of drugs which have been proposed as remedies for it. Thus, under the head of Hydrophobia I have mentioned a number of remedies which have been used or proposed, because those who may have to treat a case of this disease may wish to try some remedy, although my own experience leads me to think that almost all well-marked cases will have a fatal issue whatever the drugs employed may be.

The idea of a Therapeutic Index was taken from that in Ringer's 'Therapeutics,' and I wished to make one still more full and complete by comparing his index with those of Bartholow and H. C. Wood, with Waring's 'Therapeutics,' and with the wonderful 'Medical Digest' of Dr. Neale. After I had begun to do this, I found that a similar idea had occurred to Dr. S. 0. L. Potter, who had already published an index of 'Comparative Therapeutics,' in which he gave a list of remedies taken from the works of Aitken, Bartholow, Niemeyer, Phillips, Piffard, Ringer, Stille, Tanner, Trousseau, H. C. Wood, Waring, and some others. After finding that Dr. Potter had already compared together more works than I expected to do, I used his list, along with Naphey's 'Medical Therapeutics' and Neale's ' Medical Digest,' in preparing my Index. I was unable, however, even with the aid of these works, to make the Index anything more than a mere list of names, excepting in a few instances. So imperfect was it, indeed, that up to the last moment I intended to cancel it, and would have done so had not a case occurred in my own practice which showed me that even a mere list of drugs may sometimes be desirable. I was not unmindful of the old adage that ' Fools and children should not see half-done things,' but I felt confident that the majority of my readers would not belong to either of these classes, and so I allowed the Index to remain. My intention to cancel it, however, led me to omit an acknowledgment of my indebtedness to Dr. Potter, and I have pleasure in acknowledging it now.

My use of Dr. Potter's book has led me to include in the Therapeutic Index one remedy which the homoeopaths claim as theirs. His book contains a list of remedies taken from homoeopathic works as well as from those I have already named. The two classes of remedies are kept apart in different columns; but I find that, in one instance at least, the amanuensis whom I employed to copy out a number of the drugs from Dr. Potter's book has made a mistake in the column, and has taken 'Apis' as a remedy for tonsillitis from the Homoeopathic column. To the best of my knowledge this is the only remedy I have taken from a homoeopathic source. If any other remedies claimed as 'homoeopathic' have been introduced, they have, I think, been copied from the works of one or other of the authors already mentioned, and in Dr. Phillips's work there are some remedies mentioned without references. But as I intended up to the last moment to cancel the whole list, my revision of it was hasty and imperfect; and as I omitted to expurgate 'Apis,' I may also possibly have overlooked other remedies. If any such omission has occurred I am sincerely sorry, and I can assure the homoeopaths that it is perfectly unintentional.