749 
SURGERY, 
greatest in the middle of the pupil; while the circumference 
of the lens appears like a black ring, surrounding the white 
nucleus of the crystalline. Some rays of light are capable 
of penetrating the thin margin of the lens in its most opaque 
state: and hence, patients with cataracts are almost always 
able to distinguish light from darkness, and in the early 
stage of the complaint, discern objects best when these are a 
little on one side of the axis of vision, and not immediately 
opposite the eye. Hence, such patients also see better in a 
moderate, than a brilliant light, which makes the iris con¬ 
tract over the thin circumference of the lens. 
When the opaque lens is either more indurated than in the 
natural state, or retains a moderate degree of consistence, the 
case is termed a fnn or hard cataract. 
When the substance of the lens seems to be converted 
into a whitish, or other kind of fluid, lodged in the capsule, 
the case is denominated a millcy, ox fluid cataract. 
When the opaque lens is of a middling consistence the 
case is termed a soft, or caseous cataract. 
There is another variety of the disease, necessary to be no¬ 
ticed, the secondary membranous cataract, which is an 
opacity of the anterior or posterior layer of the crystalline 
capsule, taking place after the lens itself has been removed 
from this little membranous sac by a former operation. 
Cataracts are usually cured, either by removing the opaque 
lens from the axis of vision by means of a needle, or by ex¬ 
tracting the lens from the eye, through a semicircular incision 
made at the lower part of the cornea. The first operation is 
termed couching, or depression of the cataract; the second 
is named extraction. To these two methods may be added 
the mode of operating devised by Mr. Saunders, and which 
chiefly consists in lacerating the central part of the front 
layer of the capsule, without moving the lens at all out of its 
situation. 
Couching is thus performed:—The operator may employ, 
with equal advantage, a common slender spear-shaped 
needle. If the curved couching needle be made use of, it is 
to be held with the convexity of its curvature forward, its 
point backward, and its handle parallel to the patient’s tem¬ 
ple. The surgeon, having directed the patient to turn the 
eye towards the nose, is to introduce the instrument boldly 
through the sclerotic coat, at the distance of not less than 
two lines from the margin of the cornea, in order to avoid the 
ciliary processes. 
The exact place, to which the point of the needle should 
next be guided, is between the cataract and ciliary processes, 
in front of the opaque lens and its capsule; but, as the at¬ 
tempt to hit this delicate invisible mark borders upon impos¬ 
sibility, and may endanger the iris, it seems safer to direct the 
extremity of the instrument immediately over the opaque 
lens. Thus room is made for the safe conveyance of the in¬ 
strument between the cataract and ciliary processes, in front 
of the diseased crystalline and its capsule. Care must be 
taken, in this latter step of the operation, to keep the marked 
side of the handle forward, so as to have the point of the in¬ 
strument turned qway from the iris, The needle will now 
be visible in the pupil, and its point is to be pushed in a 
transverse direction as far as the inner edge of the lens. 
Then the operator is to incline the handle of the instrument 
towards himself, by which means its point will be directed 
through the capsule into the substance of the opaque lens, 
and on inclining the needle downward and backward, the 
former will be lacerated, and conveyed, with the latter, 
deeply into the vitreous humour. 
It is deemed of great importance to lacerate the front layer 
of the capsule in the operation; because this plan renders 
the subsequent absorption of the opaque lens more certain 
and quick. 
When the case is a fluid or milky one, the contents of 
the capsule flow out as soon as the little membranous sac is 
pierced with the needle, and they sometimes completely con¬ 
ceal the iris, the pupil, and the instrument from the operator’s 
view. The object now is to lacerate the capsule as much as 
possible. 
Vol. XXIII. No. 1605. 
When the cataract is soft, the particles of which it is com¬ 
posed will frequently elude all efforts made with the needle 
to depress them. This, however, is quite unnecessary. The 
operator may either be content with a free laceration, and 
disturbance of them, or he may imitate Scarpa in pushing 
the fragments of the capsule, and the particles of caseous 
matter, into the anterior chamber, where absorption is ob¬ 
served to becarried on with morevigour, than behind the pupil. 
When the case is a secondary membranous cataract, the 
surgeon is to turn the point of the needle cautiously towards 
the pupil, and pierce the opaque capsule. This is to be 
broken, as far as it is practicable, at every point of its cir¬ 
cumference, and the fragments may either be left in their 
situation, or pushed forward through the pupil into the an¬ 
terior chamber. 
When the capsule is adherent to the iris, it may often be 
separated by skilful and delicate movements of the needle. 
If the operator should prefer the straight needle, he must 
be careful to depress the cataract a little in the first instance, 
before making any attempt to place the instrument in front 
of the cataract, in order to be able to depress it downward 
and backward, in the most convenient manner. 
In the extraction of the cataract, by dividing the cornea, 
the knife should be so constructed as to increase gradually in 
thickness from the point to the handle; by which means, as 
Mr. Ware has observed, the aqueous humour will be pre¬ 
vented from escaping before the section is begun down¬ 
wards ; for when the aqueous humour escapes prematurely, 
the accident causes the iris to fall forward beneath the edge 
of the knife, and be wounded. 
The patient is to sit in a low chair, and not in too strong 
a light, as this makes the pupil contract too much. The 
sound eye is to be covered with a compress. An assistant 
is gently to raise the upper eyelid with his fore and middle, 
fingers, and he is to press the tarsus against the upper edge 
of the orbit. The operator should be seated a little higher 
than the patient, resting his right foot on a stool, in order 
that his knee may be raised high enough to support the 
elbow. The knife is to be held like a writing pen, and the 
little finger of the hand is to rest steadily on the outside of 
the cheek. 
When the eye is still, and so turned towards the outer 
angle that the inner and inferior part of the cornea can be 
distinctly seen, the operator is to plunge the knife into the 
upper and outer part of this tunic, at the distance of a 
quarter of a line from the sclerotica, and a little above the 
transverse diameter of the cornea. 
The blade of the knife is now to be pressed slowly down¬ 
wards, till it has cut its way out, and divided a little more 
than half of the circle of the cornea. 
The incision of the cornea being accomplished, the next 
object is to divide the anterior layer of the capsule of the 
crystalline lens, in order to allow the opaque lens itself to 
escape. Wenzel used to puncture the capsule with the point 
of the knife, at the same time that he was dividing the 
cornea. 
In general, the exit of the opaque lens very readily follows 
the division of its capsule, as soon as gentle pressure is made 
on the eye. If any fragments of opaque matter remain be¬ 
hind, they are usually taken away by an instrument resem¬ 
bling a minute spoon, termed a curette. 
A very small pair of forceps is commonly employed for 
extracting the capsule itself, when deprived of its natural 
transparency. 
Of the Back, 
The bones of the spine are liable to fractures from blows, 
and to dislocations from falls. Superficial fractures of the 
vertebrae may be felt with the finger. Fractures of the more 
deeply situated parts of the vertebrae can hardly be detected 
with certainty ; for the parts themselves cannot be examined 
and the various symptoms which usually occur, are not cal¬ 
culated to dispel all doubt, inasmuch as they may originate 
from a simple concussion of the spinal marrow. A blow, 
9 E which 
