Joke

A noted biologist, who had been studying little green frogs in a swamp, was stumped. The frog population, despite efforts at predator control, was declining at an alarming rate.

A chemist at a nearby college came up with a solution: The frogs, due to a chemical change in the swamp water, simply couldn't stay coupled long enough to reproduce successfully. The chemist then brewed up a new adhesive to assist the frogs' togetherness, which included one part sodium.

It seems the little green frogs needed some monosodium glue to mate.