he accounts effective for the construction of a binocular speculum.*

Dr. Blake has also constructed small reflecting glasses, like those used by dentists, to be inserted into the tympanum in cases of perforation of the membrane when the state of the parts admits. And it is conceivable that in some cases of minute growths or caries these might be very valuable.

In introducing the speculum, it must be remembered that (beginning from without) the meatus winds, first, a little forwards, and then backwards and slightly upwards, so that there is a tendency for the eye to fall on the wall of the meatus, instead of reaching the membrane; and the speculum accordingly must be introduced well into the passage, and directed first a little forwards, for the most part with a slight pressure on the outer part of the posterior wall, to straighten the cartilaginous portion of

* “Archiv. für Ohrenheilkunde,” 1873, p. 239. Since a really efficient instrument of this kind would probably be valuable for estimating the irregularities of form presented by the membrane, I append Dr. Eysell's suggestion, which appears as yet not to have been carried out ;-"Two prisms of small refracting angles (3°-5°) are so placed in a setting that they touch one another with their refracting edges, and that the border surface of the one lies in the same plane with the border surface of the other that is turned to the same side, and these are introduced between the reflector and the speculum, and as near as possible to the speculum; their edges must be vertical, and the border surfaces above described must run nearly parallel to the median plane of the patient. The observer now, by means of any of the customary reflectors, throws light upon the membrane through either of the prisms, and receives on the right and left eye respectively an image through each prism. With a little practice these are easily made to coincide."

E

the canal.

This will be much aided by drawing the auricle slightly upwards and backwards with the left hand. The anterior wall of the meatus projects slightly in its central part, and so not only hinders the view of the front part of the membrane, but causes the side of the speculum to project into the canal, so that I have often found a perfect examination facilitated by cutting a

FIG. 2.

:

Figure 2 represents the form of speculum I prefer the notch is seen at E. With it is shown also an instrument, that may be used for demonstrating the membrane; a prism is introduced at c, and a second observer places his eye at B. Light is admitted at D. It may be used also for other cavities besides the meatus. [Half size.]

shallow notch in the speculum, and turning that side to the front in introducing it. In very young children the passage is extremely short, and the membrane lies almost horizontally.

In the healthy state the membrane presents a surface

of a peculiar glistening transparency, obliquely placed, and of an obvious concavity. Von Troeltsh estimates the angle formed by the membrane with the upper wall of the tympanum at 140° on an average, though it varies much in different individuals. This angle bears a constant relation to certain other characters of the cranial development. In an adult cretin he found it as much as 167°, approximating thus to the almost horizontal position of the membrane in the infant. In an examination, however, which, by the kindness of Dr. Down I was allowed to make of the ears of the inmates of the Earlswood Asylum for Idiots, I did not notice unusual obliquity of the membrane.

The points which specially attract the eye and should be first sought out as the starting point of the examination, are (1) The handle of the malleus, and (2) The bright spot. The former commences superiorly with the white and prominent short process, and runs downwards, and generally somewhat backwards, as a broad white line, terminating near-but a little above and in front of the centre of the membrane at its most concave point (the umbo). The bright spot extends in a triangular form from near the termination of the handle of the malleus downwards and forwards. It is due to the peculiar curve given to the membrane by its oblique position, and concave form, together with the convex curve of its peripheral part.

The extent and form of this bright spot are somewhat

variable. Even in healthy membranes it may or may not reach to the circumference, it may be a single broad streak of light, or may be divided across or lengthwise. If the membrane moves outward, as when the tympanum is inflated, or inward as during the act of swallowing, the motion is generally most delicately marked by the changes in the appearance of the bright spot. In diseased conditions it may be wanting altogether, or from abnormalities of curvature its position may be changed, or several may be present in different parts of the membrane. The colour of the healthy membrane cannot be exactly described, because it varies with several circumstances. By virtue of its transparency its hue is modified by the rays of light reflected from the promontory, and the kind of light employed also affects it; it is more blue by daylight, more yellowish by artificial illumination.

The chief points to note in respect to the membrane are its degree of concavity; the appearance of the reflection of light from its anterior surface; the direction of the handle of the malleus across it; its transparency; its vascularity, whether there be thinner or thicker portions, or deposits, or parts especially depressed or bulging; and, finally, whether it be wanting wholly or in part, and, if it be, the condition of the exposed tympanic

* It should be remembered that prolonged examination will induce a certain vascularity of the membrane; Bonnafout also says that he has known loud sounds produce it.

wall. In addition, we must note the condition of the meatus, especially whether it be obstructed by exostoses, which not very unfrequently happens, or contain fluid, or masses of wax or epidermis, or growths of fungi. The presence of either a small quantity of opaque fluid at the bottom, or of flakes of epidermis, may be very misleading, since they may simulate very closely the appearance of the membrane in some morbid states. When a layer of fluid covers the membrane a distinct pulsation is often seen; this generally, but not always, implies a perforation.

In states of perfect hearing the membrane may present considerable varieties of appearance; differing greatly in hue, in transparency, and sometimes presenting even dense masses of chalky deposit, occupying a considerable portion of its surface. In one instance of not only perfect hearing, but acute musical sensibility, in a child, there existed apparently a solid rod of bone, running from the short process of the malleus to the posterior wall of the tympanum; apparently a malformation of the bone.*

The most usual deviation from the healthy state seen in the membrane is that characteristic of chronic catarrh of the tympanum, generally accompanied with obstruction of the Eustachian tube. The natural curvature of the membrane in this case is lost, and it is altogether drawn in, with a marked concavity. Often in such cases, if

* See Atlas, Plate XI., Fig. 5.