The author has poisoned a number of rabbits, guinea-pigs, cats, and one mouse, with fatal doses of quinine. The middle ear and the labyrinth were examined, and found in all of those cases where before the entry of the final convulsions the animals were killed by bleeding to death, that no hemorrhages or hyperæmias were present. The investigations in regard to ischemic changes in the labyrinth or in the auditory trunk were also negative. From analogy of the action of quinine on the retina, he is inclined to accept the possibility of an ischemia of the membranous labyrinth. The second part of the paper treats of the effect of quinine on the nervous system of the auditory organ.

The author believes to have discovered a specific action of quinine on the ganglion cells of the spiral ganglion.

The ganglion cells of the control animal presented sharply differentiated granulations on a red-stained protoplasma ground, while the cells of the quinine animals showed in a diffuse bluely stained protoplasma a few Nissl's bodies as dark blue granules. After prolonged differentiation, when the bodies of the normal cells have lost their blue color, the ganglion cells of the quinine. animals become as sharply differentiated as before in the normal animal. As the other bodily cells do not show such a tinctorial condition, these changes in the ganglion cells can be regarded as changes in the condition of the cell; in other words, a disturbed vital activity. DREYFUSS.

In this study of the apparent movement of objective pictures, our treatment concerns itself especially with those occurring spontaneously, caused by external influences such as acoustic impressions.

The experiment showed that impressions of sound were able to cause apparent movements, differing according to the sounds as regards their pitch and intensity. The apparent motion can be associated by a disturbance of equilibrium on the approach of a sound. Mucous or cutaneous irritation may cause an apparent

movement.

The experiments of the author on the apparent movements of objective pictures following cold irrigations of the ear, variations in air pressure in the tympanum, and the action of the galvanic current with the anode or the kathode in the canal, are, in my estimation, quite physiological processes.

The above phenomena can be produced easier on monocular vision, most easily in after images, which is treated in a second

chapter. A third chapter treats of the influence of color sensations on objective and subjective visual impressions, and a final chapter on the influencing of color perceptions by these.

The study is of interest for all of those acquainted with the audition colorée, with disturbances of equilibrium and the perception of certain tones, and especially for psychologists.

DREYFUSS.

16. It is now well established that the deviation of the head resulting from the passage of a galvanic current through the head depends upon an irritation of the labyrinth and not upon an irritation of the nervous central organ. It has, however, always been unclear how this turning of the head takes place. Does it depend upon the irritation of one labyrinth with the paralysis of the other, or the presence of both conditions at the same time in different parts of both labyrinths?

The author has attempted to solve this question. In a dove, the vestibule and the semicircular canals were exposed and electrodes applied; one upon a definite part of the labyrinth, the other about cm posterior. On closing the current, turning of the head was noticed to the exposed side if the positive electrode was applied to the labyrinth, turning toward the intact side when the negative electrode was applied to the labyrinth. The later movement was always more violent. He was not able to produce various movements of the head by placing the electrode on different circular canals or vestibule. He believes this to be due to an incomplete isolation of the various parts of the labyrinth in his experiment. After destruction of the vestibule and of the ampulla, the phenomenon cannot be produced, though it is not prevented by destruction of the greater part of the semicircular canals. The former are therefore physiologically the more important. In chloroform narcosis the reflex is also absent.

DREYFUSS.

(To be continued.)

BOOK REVIEWS.

X.-Ein objectives Hörmass u. seine Anwendung. (An Objective Hearing-Measure and its Use.) Von Prof. PAUL OSTMANN, Executive Surgeon of the University Policlinic for Ear, Nose, and Throat Diseases at Marburg, Germany. (Dedicated to Prof. Bezold.) I. F. Bergmann, Wiesbaden, Germany.

The text of this monograph occupies twenty-seven pages in 8vo; the rest, by far the greater part of the work, consists of numerous very large, repeatedly folded plates. The author criticises the methods of determining the hearing acuteness of healthy and diseased ears which have thus far been in use. The most popular of them is to note the time how much longer tuning-forks, struck with supposed equal force, are heard by the healthy ear than by the diseased one. For instance, if 150 seconds by the healthy and 75 by the diseased, then the hearing acuteness is denoted H = This and similar methods and the graphic representations of the results of the examinations of hearing by HARTMANN are wrong, as JACOBSON pointed out almost twenty years ago.

BEZOLD and EDELMANN determined the vibration periods by supposed equal strokes for forks between C and c'. The erroneousness of their statements and deductions have lately been shown by a detailed, scientific revision from JACOBSON.'

2

PANSE distinctly showed the way that would lead to the discovery of an objective hearing-measure, but he failed by underrating the difficulties inherent in the experimental solution of the problem. GRADENIGO'S optical method proved equally unsuitable for the complete solution of the problem. The author expresses the problem as follows:

1 Jacobson and Cowl. Engelmann's Arch. f. Physiologie, 1903, 1 and 2. Die Schwerhörigkeit durch Starrheit der Paukenfenster. Arch. f. Ohr., vol. xliii., p. 251, 1897.

"To determine the ringing-out curves of the unclamped forks Cand G of BEZold-Edelmann's continuous-tone series, of largest possible amplitudes down to the normal threshold value in such a manner that the amplitudes of the forks from C of the large octave to the c* of the four-times marked octave can be directly measured in second-intervals, or correctly computed from the measured values."

The arrangement to measure the amplitudes of the vibration of the forks is complicated. We can only sketch it here. The forks are screwed tight in a vice which, in its turn, is immovably inserted into a stone wall. The microscope with which the vibrations of the forks are measured is placed on an iron tableplate, which is supported by iron bars inserted into the wall. The finest dried flour dust is strewn on the end of one of the prongs of the fork, and one of the granules nearest to the edge is selected as the object of observation. The excursions of this granule are measured with the micrometer of the eyepiece, from the starting of the vibrations to their cessation.

To set the forks into vibration, an instrument similar to a Roser mouth gag, but with finer and numbered toothing, forces the prongs asunder, so that it may be released at any degree of tension and at any time. Thus the initial force of vibration can be made the same at any experiment, a condition which has proved by no means the same when the fork was struck in the usual way, even by experts.

To take observations as here described requires three persons: the first, the observer, who measures the vibrations; the second, who watches the periods of time of the vibrations; and the third, who notes the numbers of the micrometer values called out by the others.

The author has, according to this method, examined a number of soldiers with healthy hearing organs, and afterward his own (he is forty-four years old), and found his acuteness of hearing normal.

The normal amplitude of a tuning-fork is that amplitude of a fork at which its tone dies away in a normal ear; this means the normal threshold-value. The dimensions of normal amplitudes for some forks, as determined by the author, were:

g 0.0009

It has not been possible to measure higher tones, and how to

do it is a question.

The average duration of perception of the normal ears of the author was:

With this the author says we have an objective uniform hearing measure of the unclamped forks from C to c1.

These data are serviceable for practical and scientific purposes. They show how far the defective ear is below the normal ear. With three forks, C, c, and c1, we can, by the aid of the tables given in the monograph, determine the difference between the threshold values of the normal and the defective hearing organ. The author thinks that, for the present, we would do better to express the hearing-defect by the simple multiple of the normal amplitude than by its square value which, undoubtedly, is scientifically correct.

We have given a rather extensive abstract of Professor Ostmann's monograph, because it treats of a very difficult subject in an earnest spirit. His work denotes an extraordinary amount of labor and, as far as it goes, in the right way. Nevertheless we think that his work, as that of his predecessors, is only a step in the right direction. The intensity of sound is directly proportional to the square of the amplitude of vibration and inversely to the square of the distance. The tuning-fork is a very valuable means of testing the function of our hearing organ,-audition,— but it is not the only means. It has only one sound. All musical instruments, of which the human voice concerns us most, possess, besides pitch and intensity, the quality of sound," Klangfarbe " (clang-tint, timbre), which has a great influence on the audibility -i. e., the perception and conception of what we hear. The various consonants, as well as the vowels, have different degrees of audibility, which greatly depend on their pitch and intensity. The tuning-fork measures pitch and intensity, both of which are of the greatest influence on a correct diagnosis and treatment of ear diseases.

If, in practice, we want to make a satisfactory examination of the acuteness of hearing, the best way, for the present, is to deter