The Rev Dodgson said:

From Next Door:

“Three surgeons were discussing who makes the best patient to operate on.

The first surgeon said:
- Electricians are the best. Everything inside them is colour-coded.

The second surgeon said:
- No, I think librarians are. Everything inside them is in alphabetical order.

The third surgeon shut them both up when he said:
- You’re both wrong. Politicians are the easiest to operate on.
There’s no guts,
no heart,
no brains
and no spine.

Plus, the head and the butt are interchangeable.”

I heard that (a long time ago) as “Americans are easiest to operate on: they’ve only got two working parts, a mouth and an arsehole, and they’re interchangeable.