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In cafe of this Accident, it came into my Thought 
to turn the Catheter upfide-down ; fo that the Angle 
of the moveable Piece might anfwer to the upper 
Part of the Neck of the Bladder, and flop there, 
while the concave and immoveable Part of Cathe- 
ter anfwer’d to the Incifion, and that the very End 
of the Catheter projected at the Place where I was 
to open the Body of the Bladder. And, upon fevc- 
ral Trials, I found that this Place was the very fame 
which had before been pointed out by the Angle of 
the moveable Piece ; therefore, when I have one of 
thefe Catheters , on which I cannot depend, I make 
ufe of it in this laft Manner; and it intirely anfwers 
my Expectation; becaufe the fix’d Piece of thefe 
Catheters is always very folid, and that the An- 
gle of the moveable Piece does its Duty as well on 
the upper as on the under Side of the Neck of the 
Bladder. It has even feem’d to me, that the End of 
the Inftrument makes the greater Prorrufion for- 
ward. In fine, this Catheter , being almoft ftrait, 
eatily affumes in the Bladder every Situation which 
one finds neceffary to give it. 
Fig. 3. reprefents the Incifion-Knife, which I ufe. 
It is the fame that I call Urethotome in my common 
lateral Operation ; excepting that here I give a greater 
Length to the Back, 
A is the Handle ; B C the Blade ; of which B is 
the great Edge, C the Back, FE is the little Edge. 
I11 the middle of this Blade is a Chanel, that ends 
with the Point of the Inftrument at E. The little 
Edge FE muft not go beyond the Point F y if the 
Operator would fpare the Neck of the Bladder, when 
he plunges the Inftrument into this Organ ; for, if 
it 
