528 PHILOSOPHICAL TRANSACTIONS. [aNNO 1741. 



between the points ; but for the more security, somewhat lower nearer the os 

 pubis ; then without drawing out the knife, make a large incision downwards 

 inclining under the arch of the pubis, in proportion to the size of the stone, 

 taking care not to wound the cartilage that joins the bones together, when the 

 knife is withdrawn. The bladder being thus supported, the stone may be ex- 

 tracted with the fingers, or with a small pair of tenets, there being little danger 

 of breaking it in this method. When the operation is finished, raise the handle 

 of the catheter, and unbolt it ; shut it close, and fix it so ; then withdraw the 

 catheter, and dress the patient. 



Fig. 1. pi. 12, represents the catheter as it is to be introduced into the blad- 

 der, the 2 legs A and b being closed together. 



Fig. 2. The catheter, its 2 legs a, b, being open, c, d, the tube ; e, the 

 sliding-bolt ; p, the two holes into which the bolt is to be slid ; g, the ears 

 fixed to the tube c, d, which is all of one piece with the leg a ; h, the handle, 

 which opens the legs ; this handle is all of one piece with the leg b, which b 

 is a continuation of a wire, that runs through the tube c d, and is fastened to 

 the handle h, and turns with it. 



Of Needles made for Operations on the Eyes, and of some Instruments for the 

 Ear. By the Same. N° 461, p, 847- 



The first differs from a common couching-needle (fig. 3, pi. 12) in this, 

 that it is made of two pieces of steel soldered together, and fixed in a handle 

 (fig. 4) : at a little distance from the handle they separate, and have, in each 

 lamina, a button fixed, which passes through a hole in the other ; from this 

 part to the points, they are so nicely applied, and polished together, that they 

 cut, and have the shape of a common needle. On pressing the buttons, the 

 points are separated, and in the inside of the broad part of the points are se- 

 veral small indents, to prevent any thing from slipping, after it has once got 

 hold. 



The use of this needle is, either to depress a cataract; or, if it should be 

 found of such a nature as to bear to be taken hold of, then, by opening the 

 points, to engage it, and carefully bring it out of the eye. 



If it should happen, that in dressing the cataract, or in bringing it out of the 

 eye, some of the small vessels are wounded, and some drops of blood diffuse 

 themselves in the aqueous humour ; this second needle (fig. 5.) is intended to 

 remedy this inconvenience. 



It is a long, small, round stilet (fig. 6.) gradually decreasing from the handle 

 to the point ; and is fitted to a long silver tube of the same shape, (fig. 7.) 



