In this new edition the work has undergone thorough revision, and has been increased in size by two hundred pages, with several new plates. In the matter of illustrations, the volume is especially fortunate, since it has 190 of these and 25 full-page plates in color and black. The practical character of the work merits the attention of the general practitioner as well as the specialist.

Howe's Handbook of Parliamentary Usage. Arranged for the Instant Use of Legislative and Mass Meetings, Clubs and Fraternal Orders, Teachers, Students, Workingmen, and all who desire to conduct themselves "decently and in order" in public assemblies. By Frank William Howe. Price, 50 cents. Published by Messrs. Hinds & Noble, 31-33-35 West 15th Street, New York.

A knowledge of parliamentary usage should be of great value to physicians, as no class of men are more frequently called upon to engage in debate. However, comparatively few physicians seem to know even the rudiments of such usage. This little work by Howe will prove useful in imparting much information. cleverly arranged, convenient in size and reasonable in price.

It is

A Laboratory Manual of Physiological and Pathological Chemistry. For students in medicine. By Dr. E. Salkowski, Professor in the University and Director of the Chemical Laboratory of the Pathological Institute, Berlin. Authorized translation from the second revised and enlarged German edition, by W. R. Orndorff, A.B., PH.D., Professor of Organic and Physiological Chemistry in Cornell University, with ten figures and a colored plate of absorption spectra. 8vo, vii and 263 pages, illustrated. Cloth, $2.50. John Wiley & Sons, New York.

Physiological chemistry has a most important bearing upon medicine, and should be taught thoroughly in every medical school in the country. It really deserves much more prominence and attention than the ordinary course in chemistry, for it will prove of far more value to the student when he goes out into actual practice. Salkowski's work is well known to German readers, and is generally used in the German universities, so we are quite glad to see that Professor Orndorff has made such a clever translation of the work into English. In this form it should rapidly become popular with American students, for it has not the objectionable feature of voluminousness, and may be regarded as the joint product of two of the best known teachers of physiological chemistry in the world.

Diseases of the Eye. By L. Webster Fox, A.M., M.D., Professor of Ophthalmology in the Medico-Chirurgical College of Philadelphia, Pa.; Ophthalmic Surgeon in the Medico-Chirurgical Hospital. With five colored plates and 296 illustrations in the text. Published by Messrs. D. Appleton & Company, New York and London. 1904.

The author has in this work presented the results of ten years as a lecturer on ophthalmology, for he has taken as its base a series of lectures delivered during this period at the Medico-Chirurgical College and Hospital. The result is a practical work, which will appeal to not only the specialist, but also the general practitioner and student. The author is well known for his scientific contributions to the subject of ophthalmology, and an extensive experience in the practice of this science has been valuable to him in the production of a treatise which will

not merely be glanced over and laid aside, but which will constantly be consulted on account of its careful regard for the many details in diagnosis and treatment, so important in the routine of practice.

The typographical execution of the book is more than ordinarily good, and the illustrations, of which there are 296 in the text with five colored plates, are particularly clear and accurate. We regret to see that the author uses the archaic form of spelling such words as color, using the superfluous u, which is not American, and which is not justified by the origin of the words thus spelled.

Infant-Feeding in Its Relation to Health and Disease. A Modern Book on All Methods of Feeding. For students, practitioners and nurses. By Louis Fischer, M.D., Visiting Physician to the Willard Parker and Riverside Hospitals, of New York City; Attending Physician to the Children's Service of the New York German Poliklinik; Former Instructor in Diseases of Children at the New York Post-Graduate Medical School and Hospital; Fellow of the New York Academy of Medicine, etc. Third edition, thoroughly revised and largely re-written. Containing 54 illustrations, with 24 charts and tables, mostly original. 357 pages, 53 x 8 inches. Neatly bound in extra cloth. Price, $2 net. F. A. Davis Company, publishers, 1914-16 Cherry Street, Philadelphia, Pa.

Dr. Fischer has been a frequent contributor to the literature of infant-feeding, and this work of his enjoys more than ordinary vogue, being now in its third edition. The bearing of infant-feeding in its relation to health and disease is so important that any information that may lead to the solution of vexing problems in this connection is eagerly received. The experience of the author is large, and his observations have led to deductions which have the usual value appertaining to the opinions of men of professional eminence gained through merit. Every practitioner of medicine will find much in this book that he can use in active practice.

The Man Who Pleases and the Woman Who Charms. By John A. Cone. Published by Messrs. Hinds & Noble, 31-33-35 West Fifteenth Street, New York.

While from the title of this little book one might be inclined to believe that it indulges in a kind of society sophistry which would make it absurd to the thinking reader, yet it contains the surprise of so much intelligent information on social deportment, dress, etc., that the reader who peruses the book will be delighted with its every line. As the author says, "Courtesy is not the least of the Christian virtues, and it should be studied as an art." The reader of this book, no matter how well bred, cannot fail to find therein some suggestions which may be profitably adopted in the future.

THERE are phenomena and properties in connection with currents of high tension that do not conform to the old laws of electro-physics, at least, they are not measurable by the accepted standards of unit. Every one knows that a volt is the unit of electromotive force and is the amount of force necessary to overcome the unit of resistance, which is the ohm. An ordinary galvanic cell may generate an electromotive force of from 40 to 60 volts, but the fluid within the cell forms a dielectric through which the current has to break in order to make the circuit. This internal resistance reduces the available voltage to something under two volts in the very best cells.

A static machine may generate considerably upward of a million volts and still fail to light a tube that another form of current, from a coil, for instance, would light with half the voltage or less. This difference in overcoming resistance can, therefore, not be expressed in terms of volts. When a static machine is set in motion, the revolving plates produce a friction upon the air corpuscles, which friction is in proportion to the speed of rotation. A vibratory form of current is thus generated, in which, at a given rate of speed, the amplitude Vol. 24-17

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of vibration is inverse to its rapidity-in terms of soundphysics, the former is called intensity, the latter, pitch. It is the high-pitched current which has the property of overcoming the resistance above mentioned.

This adjustment of the pitch and intensity to produce a current of proper "tension" can be done to a nicety in a Ruhmkorff coil fed by a constant current. In this the "secondary" winding is made of many miles of fine, well-insulated wire and the interruptions are made by a "break" which is sharp and free from secondary reverberations and which can be regulated so that an extreme frequency of discharges into the secondary takes place. Such a coil, provided with a proper condenser, a volt meter and am-meter, fed by a street current of 110 volts, direct current, supplied through a good rheostat, gives the ideal output for X-ray work, as it can be controlled to a nicety. Such a current is not readily available, storage batteries "eat themselves up" when not in use, the outfit is very expensive and apt to break down in inexperienced hands and it is very destructive to tubes, as it furnishes such a great surplus of energy which, in our eagerness to see well, we never fail to draw upon. Alternating current coils are also made, but static machines possess such a great range of utility in electrotherapy and can stand such an amount of abuse that they are generally preferred by the occasional user in this country.

A static machine having a large number of plates gives a high voltage, even with low speed as when turned by hand, but the objection to hand power is that the output is jerky and irregular, especially when the operator begins to tire. A glass plate machine only gives good results in dry weather, giving too much current on a cold dry morning and very little or none at all on a steamy July day, since glass condenses moisture readily and many-plate machines have an immense surface for such condensation, and the same is true of dust, which is a good conductor for static currents. Such a machine cannot bear a high rate of speed, as the centrifugal force would disrupt the plates, hence the deficit has to be made up by the number of plates. Such a machine will give beautiful, long sparks when new and dry, but its output is a current of low pitch. The length of spark depends upon the size of

plates and the "set" of the neutralizer, but this has no value whatever for good X-ray work. Practically, a six-inch spark of good volume (flame-spark) answers every purpose with a good tube, and a poor one is undesirable for any purpose. On the other hand, a machine capable of developing a speed of 2000 revolutions gives a current of high pitch and intensity and good volume, because the molecular vibration of air particles is from five to seven times as great as that from a lowspeed machine, and in this respect it is more like a coil in the character of its output.

Another error of construction in many static machines is the amount of surface exposed to the conducting influence of damp air on the outside of the case. A vast array of showy brass balls may be very imposing to the spectator but at best brass is cheap and the greater amount of atmospheric leakage is not compensated by this glitter of cheap display.

It has been urged that a composition plate machine, such as the one designed by Dr. Wagner, requires too much attention and the ball bearings of rapidly revolving machinery need care, but is it not worth something to have an apparatus that can be depended upon at any hour of any day in the year? If used a great deal, it will need a good deal of cleaning but in that case it is earning money, and here I wish to enter my protest against the practice of allowing every one a❝look at his hand," or to use the machine for any purpose without demanding a substantial fee for the work. The practitioner is respected, all things being equal, according to the size of his fees, and he cheapens himself in the estimation of his clients when he does things for nothing. No one lacking experience should attempt to operate an X-ray apparatus, as it is fraught with dangers and may become the source of malpractice suits. I beg your indulgence to recall such a case:

A very competent surgeon came to my office one Sunday about noon to have an elbow examined. After he had looked at it for some time whilst I was busy adjusting the machine so it would give its best output, the current to the motor was cut off by the engineer, who, like all good workmen, never works overtime. The surgeon expressed himself as satisfied with what he had seen. Two weeks later another surgeon brought the same patient to me, and this time I made the