Reviews and Notices
BMJ (Clinical Research Edition)
A PRACTICAL INTURODUCTION,TO MEDICAL ELECTRICITY. By A. DE WATTEVILLE, M.A., M.D., B.Sc. Second Edition, with eightynine Illustrations, and Plates of the Motor Points. London: H. K. Lewis. 1884. W'E have transcribed the statement on the title-page that the volume before us is the " second edition," but it would be more correct to say that Dr. DE WATTE4ILLt, having once written a book on medical electricity, has now written another and a better. The tone of the book is thoroughly scientific;
... hly scientific; and, if the views and hopes expressed with regard to the therapeutic application of electricity appear at times over-sanguine, this is only what we must expect, and indeed desire; for, unless the advocates of a somewhat novel means of treatment be possessed by some little enthusiasm, there is not much hope that it will be pushed into general use. Dr. de'Watteville believes that he has found a happy mean between excessive enthusiasm and premature discouragement, and perhaps he is right. 'Though thus not wanting, in enthusiasm, he most sternly warns away the mere dabbler in electro-therapeutics, and insists, first, that the laws of electricity should be understood; and, secondly, that it should be used in an intelligent manner and in measured quantities. The first chapter, therefore,1on electro-physics, which takes up nearly half the book, very fully and explicitly lays down and explains the laws of electricity, from the most elementary to the more abstruse; so that a person really desiring information, but quite ignorant of the subject, may take up the study of this volume with the conAftence that every step will be -thoroughly discussed and explained. We are aware that the Doctor of Medicine who stands' in need of such instruction ou&ht to be as extinct as'the dodo; but we fear that, in spite of preliminary examinations in science, the general diffusion of ignorance is still very considerable. Indeed, were this otherwise, were our present means of teaching and learning science more efectual, there would still remain a necessity for such a chapter as this on electro-physics; for electricity is a comparatively young science, and is constantly moving in the direction of greater precision. Especially is this the case with regard to measurements of current-strength; and upon this point Dr. de Wstteville, as the readers of his first volume may remember, has very tstrong opinions. He'recommends the use of the galvanometer gradu--ated in milliamperes, which enables the physician to measure and register, for future reference and comparison, the strength of current used in every instance, to compare the resistance in the circuit, and to ineasure the electro-motive force in circuit. The "ampere" is the unit of current-strength adopted by the International Congress of Electricians; the milliampere is the thousandth part of an ampere, and is the most convenient unit to use in electro-therapeutics, as its multiples correspond to the strength"of currents which can be advantageously used in therapeutics. A current of one milliampere, about the weakest ever so employed, is yielded by two to four Daniell's cells, when the parts of the human body usually selected are included in the circuit by means of two electrodes of nioderate size. Granting readily that this accuracy of measurement is a consummation devoutly to be wished, it is yet to be feared that it will be long before the use of the galvanometer becomes the rule rather than, as now, the rare exception; and this chiefly because of the difficulty of obtaining a really trustworthy instrument at a moderate price. If that difficulty can be overcome, then a comparatively short time will be required to accomplish a much needed reform. The galvanometer is, of course, only capable of measuring the strength of continued currents; and there exists, as yet, no instrument for measuring the strength of faradic currents. The only measurement of the faradic current which can be employed is based on the measurement of the distances between the secondary and primary coils; but the results thus arrived at cannot be compared from instrument to instrument. But, though this is the case, Dr. de Watteville shows that the galvanometer can be of the greatest service when used to ascertain the degree of resistance encountered by the current. For instance, let us suppose that, in making an examination of the ulnar nerves on the two sides, we find that the left ulnar is excited when the coils of the faradic apparatus are 200 millimetres apart, and that we have to raise the graduated bar until the coils are only 150 millirzetres apart in order to excite the right ulnar, it is very *iatural and very common, but quite erroneous, to assume that the electro-excitability of the right ulnar nerve is less than that of the left. Au examination with the galvanic current and the galvanometer is now necessary, in order to ascertain the resistance encountered in the tis-AROes; and, if it should result from this that the resistance on the right side is greater than on the left, in about the proportion mentioned above, then it would appear that the excitability of the nerve was the same on both sides; the increase in strength being required, not to stimulite the nerve, but to overcome the resistance in the tissue. The descriptions of apparatus, batteries, coils, collectors, rheophores, and electrodes, are clear, and the advice as to the choice of these instruments judicious. The chapters on electro-physiology and electro-diagnosis are worthy of careful perusal, especially the latter, in which the difficult and rather obscure subject of the " Reaction of Degeneration " is dealt with in a masterly manner, which makes clear one of the dark places of neuropathology. Dr. de Watteville has stated in forcible language the difficulties of electro-diagnosis, and has emphasised the need for caution and experience; but it must be allowed that the nature of the difficulties has not permitted him to do much towards diminishing them. Still, if a difficulty that is known be half surmounted, then the careful student of Dr. de Watteville's book will have advancel one step; constant practice will alone enable him to take the next. Having thus cleared his subject of obscurity and ambiguity, Dr. de Watteville is able to deal with the application of electricity to the cure of disease in a succinct and practioal way, which renders the chapter on electro-therapeutics very valuable for reference in the consultingroom; and its usefulness from this point of view is enhanced by the addition of six plates of the " motor points." Altogether the book is to be thoroughly recommended as at once scientific .and practical; indeed, it is a good example of the fact that a clear scientific comprehension of a subject is by far the shortest road to the successful practical application of a method, the true royal road to learning. ON THE TREATMBNT OF SPINAL CURVATURES BY EXTENSION AND JACKET, ETC.