telescope 10 as indicated previously the telescope shaft 96 is isolated electrically from all other conductive material at the ground or patient plate potential accordingly even if it should be touched by the electrode the resulting effect would be minimal and no harm should be done to the telescope referring now to fig1 of the drawings a second embodiment of the working element stem portion 26a of the resectoscope according to the invention will be described the use of alphabetical letters in connection with numbers for certain parts in this specification and in the drawings is to identify the parts which are the same in each of the various different embodiments the stem 26a includes a telescope channel member 44a and electrode guide channel members 46a as in the preferred embodiment but instead of having these guide channel members seal directly against the sheath 16a as in the preferred embodiment a cover 138 is provided which seals against the guide channel members 46a on one side and nests snugly against the sheath 16a on the other this cover 138 extends the length of the stem 26 including the portion of it forming the roof 50a this cover includes at least one slot or other opening not shown adjacent the drainage openings 57 in the sheath see fig2 amp 8 to facilitate the passage of irrigation fluid into the drainage conduit in all other respects this second stem embodiment is like that of the preferred embodiment referring to fig1 a third embodiment of a working element stem 26b according to the invention includes telescope channel and electrode guide channel members 44b and 46b respectively but instead of a cover as in.