Anyone who has a knowledge of the higher branches of mathematics fresh in mind will readily comprehend the principle underlying this method. There are others who can understand how the first negative will indicate the distance of the foreign body back of and above or below the center of the cornea, but they will ask, as I have been asked, if the two negatives together will always show whether the foreign body is in the temporal or nasal half of the eyeball.

Such persons may, perhaps, derive benefit from a study of the above diagrams, which are intended to represent the left eye containing two foreign bodies, one in the temporal half and one in the nasal half, each the same distance below and back of the center of the co

nea.

Note: B is the ball; C the cone; F and G are the two foreign bodies.

In the first negative B and C coincide upon the negative, likewise F and G. Both F and G are 8 millimeters below B and C, and a horizontal line is accordingly drawn on the chart 8 millimeters below the horizontal lines passing through the center of the cornea.

In the second negative F is 13 millimeters below B

and 5 millimeters above C. These measurements are applied upon the chart and a line drawn through these points. This line intersects the line obtained from the first negative in the lower nasal quadrant and shows the location of F. G is shown on the second negative to be 13 millimeters below B and 2 millimeters below C. These measurements are made upon the chart and a line drawn through the points.

This line intersects the line made from the first negative in the lower temporal quadrant and this shows the location of G.

The reader may also get a heightened conception by holding the illustrated page with the edge toward him, slightly below the level of vision and looking at it glancingly, so to speak, along the lines representing the direction of the rays.

Again the reader must be reminded that these drawings are only diagrammatic; and the ball, cone and foreign bodies are thus shown in the same vertical plane. In the actual negative they will appear in different planes, hence the necessity of extending lines through the axes of the ball and cone, and making measurements in the plane vertical thereto.

tion of the foreign body as viewed from the front, whether above or below the center of the cornea, and whether to the temporal or nasal side. (See foot-note page 85), since these lines represent the direction of the rays at each exposure.

Again, upon the first negative, the distance of the foreign body from the anterior surface of the cornea, is determined by measuring from the ball along its axis, to the perpendicular through the foreign body and deducting 10 m.m. for the rebound of the ball when the trig ger was released.

Upon the chart a line is then drawn from the point of intersection in the front view, parallel to the line going through the center of the cornea, into the horizontal section, and the distance from the front of the cornea measured and indicated. In a like manner a line is drawn from the point of intersection in the front view, parallel to the chart line going through the center of the cornea, into the side view, and the distance measured back from the center of the cornea.

In making the lines and measurements upon the negatives and charts, extreme accuracy should be sought for, since an error of only a millimeter in measurement may under certain circumstances lead to a more considerable er

ror in fixing the location of the foreign body, To this end the lines upon the negatives and charts should be made with a draughtsman's pen and using red ink for greater contrast. These remarks apply most particularly to those cases in which the foreign body is in or near the sclera-the borderline cases.

The oculist should not be expected to rely upon a single localization, but the finding should be confirmed by at least one or two additional exposures, and in case of discrepancy plates should be made until the localization is satisfactory.

When the foreign body is in the vitreous it is liable to changes of location. In such cases the X-ray localization should be made with extraordinary care, and directly before operative procedure.

The importance of radiographing the eye as soon as possible after the injury, and before photophobia has become pronounced should be emphasized. In one case referred to me I found it absolutely impossible to locate the foreign body, because of the intense photophobia and the incessant rolling of the eyeball.

If on transillumination the maxillary antra are dark, it does not necessarily mean that pus is present. Thick granulations may be covering the antral wall.-American Journal of Surgery.

THE DIAGNOSIS OF AFFECTIONS OF THE LABYRINTH.

BY C. FREDERICH PFINGSTEN, M. D., St. Louis,

Instructor in Otology, Washington University.

During the past few years much valuable knowledge has come to us principally through the painstaking work of Robert Barany, of Vienna, pertaining to the study of the physiology and pathology of the static labyrinth.

By the presence or absence of nystagmus in relation to affections of the semi-circular canals we are enabled to diagnose irritations and inflammatory conditions in the labyrinth, and thus many of the stumbling blocks in the path of positive diagnosis in these affections have been cleared away. Not only by a knowledge of the presence of spontaneous nystagmus but of the ability to produce nystagmus mechanically or artificially the degree of the functionating power of the labyrinth is established.

The Vestibular apparatus consists of the three semi-circular-canals, the Utriculus and Saculus. Of importance, is the position of the semi-circular-canals and their ampullae to the head in the upright position, and their relation to each other in their various levels. The membranous labyrinth which contains the endolymph within is of special importance as it contains in the ampullar extremities the mechanism which produces these phenomena. In the ampullae are situated the peripheral nerve endings of the vestibular nerve, the Christa Ampularis and the hair-cells which are the sensitive epithelia. The latter are intermingled by a homogenous mass called the cupula and

extends somewhat above the center of the canal. When the endolymph is set in motion it produces a jar to the Cupula which causes an irritation upon the hair of the hair-cells. This irritation is to be considered as a reflex irritation which is transmitted to the center. The Vestibular nerve after leaving the Vestibular Genglion in the inner ear go to the neuclei of the Vestibular nerve which is in the region of Duters neuclei and situated in the outer extremity of the Medulla Oblongata. From these neuclei on the one hand crossed and uncrossed fibres go to the neuclei of the eye muscle nerves. On the other hand crossed and uncrossed fibres pass downward to the motor cells in the anterior horns of the spinal column. Whether fibres go directly to the cortex or whether all first go to the neuclei of the eye muscle nerve has not been determined positively. The fibres connected with the eye muscle neuclei produce the reflex eye movements which are caused by Vestibular irritation. The fibres which go to the spinal cord produce disturbance in equilib

rium in Vestibular irritation and those that go to the cortex produce the perception of Angle motion during turning, and when the body is at rest, the imaginary perception of the turning of the body.

Purkinje as early as 1825 had observed nystagmus during and after the turning of patients, but attributed this phenomena to a displacement by the centrifugal force. Flourens about the same time discovered that when the semi-circular-canal of the pigeon is severed there develop severe movements of the head and entire body in the level of the canal injured. Mach and Bruer consider the semi-circularcanals as an organ for the perception of anglemotion in turning, namely, that at the beginning of the turning and after prolonged turning the changes in the speed of the rotation are perceived by means of the semi-circularcanals. Ewald prepared the right horizontal semi-circular-canal of a pigeon and drilled a hole into it several millimeters from the ampulla towards the smooth end of the canal and filled the lumen with a mass in such a way that the membranous labyrinth was completely compressed at that point. Between the mass and the ampulla a second opening was drilled to which he attached a pneumatic hammer consisting of a small glass capillary tube with a plunger, the one end was fastened to the semi-circular-canal and to the other was attached a rubber tube and bulb. By this means of shutting off the membranous canal towards the smooth end the flow of endolymph could be controlled and studied thus by the compression of the bulb of the pneumatic hammer the plunger compressed the membranous-labyrinth, and directed the endolymph towards the ampulla. By releasing the bulb or aspiration, the opposite effect was produced on the canal. Thus by compression on the membranous labyrinth a slow horizontal motion of the head took place towards the opposite side which represents a horizontal nystagmus towards the right. When aspirating the plunger a slow horizontal movement took place, which represents, horizontal nystagmus, towards the left. These tests prove the dependence of definite eye and head movements to the direction of the endolymph in a particular canal. The same facts could be demonstrated with the vertical canals as well as the horizontal.

For Clinical purposes we induce a nystag mus artifically in various ways. First by turning the patient while he is sitting on a rotary chair a definite number of times with the head either in the vertical axis or bent forward at an angle of 90 degrees. With the head in the upright position after a definite number of turnings, say ten, the endolymph in the horizontal semi-circular-canal is set in motion.

With the head bent forward at an angle of about 90 degrees the verticle canals are thrown into function. The latter procedure is the one we principally use for practical demonstration. The scope of this paper does not permit my entering into detail of the complex varieties of nystagmus that can be induced by other positions of the head. The nystagmus is produced by rotation towards the right or left according to the side to be examined. The two principal forms of nystagmus are the undulating in which both movements follow in rapid succession, so that it is impossible to speak of a definite direction of the nystagmus. The other is of the so-called rythmic nystagmus in which we can always differentiate between a slow and rapid movement. A nystagmus originating in the static labyrinth is always of the latter type. Another peculiarity of a Vestibular nystagmus is that it becomes more pronounced when the individual glances in the direction of the rapid movements. It becomes feebler while glancing in the direction of the slow movements. We differentiate the nystagmus always according to the rapid movement. In rotatory nystagmus we determine the direction of the movement by the upper end of the perpendicular Iris Meridian. It is also intensified by glancing in the direction of the rapid movements. In producing turning nystagmus it is necessary to understand exactly what takes place in the various canals. In speaking of turning for instance, the patient is turned in the opposite direction to the side to be examined. Thus if the right ear is to be examined the patient is turned to the left; if the left ear, he is turned to the right. In order to remember what turning to the right and left means, we have only to recall the direction as given in military command "Right-about-face," It thus follows that at the beginning of the turning, the endolymph flows in the opposite direction to the turning. If the turning is continued any length of time it gradually comes to rest, and remains stationary. When the rotation ceases the endolymph then again flows in the direction in which the canal has been turned, that is, from the ampulla to the smooth end. As Ewald demonstrated, the first movement of the endolymph from the smooth end to the ampulla produces a nystagmus towards the right in the direction of the turning. When the semi-circular-canals are brought to rest the endolymph flows in exactly opposite direction from the ampulla to the smooth end and produces a nystagmus toward the left. We thus see that the nystagmus developed after turning is exactly opposite to the nystagmus during the turning. For clinical purposes we turn the patient 10 times and measure the duration of the nystagmus with a stop-watch. At the mo

ment the turning ceases the watch is started and the moment the nystagmus diminishes the watch is stopped; and thus the duration of the nystagmus ascertained. The duration of the average nystagmus in the normal is from 15 to 20 seconds. However, there are decided variations in this respect and we may have a nystagmus of 30 or more seconds duration without it having any pathological significance, but there must be a more or less uniform duration on both sides. Thus if there is a nystagmus of 25 or 30 seconds to the right and to the left side, it does not mean anything significant, but if there should be a nystagmus of 5 seconds duration on one side and 20 on the other, you can readily see that the Vestibular apparatus which had only a nystagmus of 5 seconds duration was nearly out of function. The pathological nystagmus is always of rotatory type and is always seen in the spontaneous variety due to Vestibular irritation. Caloric nystagmus is induced by injecting water into the external auditory canal of a temperature above or below the normal. When water of a low temperature is injected a nystagmus is produced towards the opposite side. When water above the normal temperature is used nystagmus is produced towards the injected side. The explanation of this phenomena is that the cold water thrown into the Auditory Canal against the outer wall of the labyrinth lowers the temperature of the endolymph, which thereby sinks to the bottom of the canal and thus a sort of circulatory movement takes place in the semicircular canal. Injecting hot water causes the circulatory movements to take place in the opposite direction. These phenomena can be produced even with an intact drum membrane. Barany uses for this purposes a Politzer bag to which he attaches a piece of rubber tubing and a Hartman attic Canula. This method of examination can be pursued even while the patient is in the the recumbent position but should not be employed where dry perforations in the drum membrane exist on account of the inflammatory process liable to be set up by cold water irrigations. Nystagmus can also be produced by compres sion and rarefaction in the external auditory canal. This can be produced by using a Politzer bag with an olive tip fitting snugly into the opening of external canal. When the bulb is compressed a decided nystagmus of several seconds duration is produced if a fistulous tract exists. The galvanic nystagmus is produced by placing the Cathode in front of the right ear and the Anode in the right hand; then a rotary nystagmus is produced towards the right. If the Anode is placed in front of the right ear and the Cathode in the right hand, a rotatory nystagmus is produced towards the left. The

amount of current used in making these tests is from 2 to 4 m.a. The galvanic nystagmus is best seen by having the patient glance in the direction of the rapid movements. This method of examination is not absolutely reliable as Dr. Neuman of Vienna was able to produce a galvanic nystagmus by placing an electrode against the inner wall of the boney cavity from which the labyrinth had been extricated.

How

ACUTE LABYRINTHITIS-Acute labyrinth destruction is produced by labyrinth supporation, by hemorrhage in the labyrinth. Arterial Sclerosis, Leukaemia, Syphilis of the labyrinth, and fracture of the base, etc. The symptoms of labyrinth destruction are universally the same. Immediately after injury, violent nystagmus of the rotatory and horizontal type take place towards the healthy side. The typical accompanying phenomena are severe dizziness, imaginary turning of objects, imaginary turning of one's body, nausea and vomiting, with disturbances of equilibrium. The patients are obliged to resume the recumbent position which is very typical: namely, they lie on the healthy side. The object of this, that they observe what is going on in their immediate vicinity reflexly by glancing towards the diseased side in which the nystagmus and the accompanying phenomena attains its minimum intensity. The phenomena lasts two or three days after which the nystagmus and accompanying phenomena gradually diminish. After removal of the labyrinth the nystagmus does not disappear suddenly but gradually. ever, it disappears more rapidly than when the diseased organ is left at rest. This is due to the fact that even though the end organ does not respond to the Caloric or mechanical irritation, the pathlogical irritations are continued towards the center; which consequently can not adapt itself as readily to the changed condition; as when the pathlogical foci are en tirely removed, often a horizontal nystagmus develops towards the diseased side after the cessation of the rotatory nystagmus towards the healthy side. After two or three weeks there is a condition known as A Latent Labyrinth Destruction. In these cases the diagnosis can only be made by means of the Caloric and Rotatory tests. A Caloric test is usually sufficient and no change is observed in the spontaneous nystagmus. In cases in which Choles teatom is present in the Auditory canal or in which very violent acute inflammatory process is present the absence of the Caloric action might be doubtful and in such cases the ro tatory test must be employed. Barany ob served in several cases where the labyrinth had been destroyed for some time after the development of the latent stage there occurred a di