[Illustration: Pl. IV.
_F.F. Giraud del^t._ _J^s. Basire sculp^t._]
_Fig. 1._
Gives a view of the director used in the operation on a child under five
years of age, slightly curved towards the extremity, the more readily to
adapt itself to the concavity of the bladder when held in the position in
Plate II.
_Fig. 2._
The knife with a scalpel blade, but longer than a common scalpel, and
slightly convex on the back near the point, that it may run smoothly
along the groove of the staff. When used with a staff of this form the
whole of the cutting part of the operation may be easily performed with
it.
_Fig. 3._
The size of the calculus which was extracted in the first operation with
these instruments is here delineated, in order to shew the extent of the
opening in the cervix vesicæ and prostate gland, which in so young a
child may be made with safety, according to the method explained in Plate
III. The comparative size of the incision that can be made in the adult
may be inferred.