288 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. 



over-agalnst, and somewhat higher than the patient : an assistant holds the 

 head steady, another keeps the upper eye-lid open ; he, with his left hand, keeps 

 open the lower eye-lid. He then takes an instrument like a lancet, of a myrtle- 

 form point, a little crooked upwards, and fixed in a handle, and, making the 

 patient look upwards, he pierces the cornea transparens at its lower circumfe- 

 rence, just where it joins the sclerotica, conveys the point of the instrument 

 between the cornea and iris upwards, beyond the pupil ; he enlarges this open- 

 ing on each side by the same instrument : he then takes out this instnmient, and 

 introduces another of the shape of a narrow lancet, made round at the point, 

 fixed in a handle : with the cutting sides of this he enlarges the opening. Tak- 

 ing out this, he introduces a pair of crooked scissars, enlarges the opening on 

 each side by different snips, always as near as he can to the circumference of the 

 cornea transparens, till he has made the opening round two-thirds of the cornea 

 transparens : he then takes out the scissars, and, with a small instrument like an 

 ear-picker, he raises the cornea, and having in his right hand a cataract-needle, 

 broader and stronger than the common, and pointed like a lancet, he cuts the 

 capsula of the crystalline through the pupil ; then, pressing gently the globe of 

 the eye with his finger from below upwards, the crystalline slips out of the cap- 

 sula, and drops out of the eye. On the first puncture, the aqueous humour 

 coming out, the cornea and iris join together : and it requires great dexterity, 

 and a very steady hand, to introduce the instruments so as not to wound the 

 iris, which would endanger the eye. 



Though the operation lasted above 2 minutes, the patient never complained of 

 any pain ; and said he felt nothing but a tickling. By which it appears the cor- 

 nea is not much more sensible than the nail of one's finger. And this operation, 

 which seems so cruel to a by-stander, does not give so much pain as couching in 

 the usual manner. It is to be preferred to couching in many respects. It may 

 be performed at all times, and in all kinds of cataracts, whether they are come 

 to maturity or not. It also avoids many inconveniencies and accidents, which 

 often baffled the success of the best operations ; such as the rising again of the 

 cataract, violent defluxions and inflammations, which often destroyed the eye, 

 the hurting of the vitreous humour, which seldom failed in couching, &c. In 

 both the operations, which Dr. Hope saw, the patient, immediately after^ could 

 distinguish all large objects in the room. 



M. Daviel says, that he has found by experience, that all those instruments 

 are necessary : and as to the extent of the incision, he says that he seldom 

 makes it above one-half of the circumference of the cornea transparens; and that 

 a smaller opening would not suffice to let the crystalline slip out easily ; the dia- 

 meter of which, in general, not being above a line less than that of the cornea, 

 and in some cases within half a line, insomuch that, in order to make it pass 



