It's to keep the elephants away

"The Psychiatrist was escorting a patient from one Psychiatric Hospital to another.
They were travelling by train, and the Psychiatrist was intrigued to see the patient
tearing up bits of paper and throwing them out of the window.

'What are you doing that for?' asked the Psychiatrist.

'It's to keep the elephants away !' answered the patient.

'But there are no elephants in Surrey,' pointed out the Psychiatrist.

'Effective, isn't it?' was the logical answer."