First Lady Coolidge, with a small entourage, preceded – by a mere few minutes - her husband, President Calvin Coolidge, on a tour of inspection of the chicken farm of a notable and valued political sponsor. Only the latter small coincidence would ever have persuaded either to be there, in the first place.

As she passed a chicken pen, she inquired surreptitiously of the man in charge, whether the rooster copulated more than once a day.

‘Oh, dozens of times!’

he rejoined helpfully, struggling hard to keep a straight face.

‘Tell that to the President when he happens along!’ she ordered.

The man duly passed on the message when the President happened along.

‘And does the rooster always choose the same hen?’ he enquired.

‘’Oh no! A different one each time!’ the man replied.

‘Tell that to Mrs Coolridge’, said the President.

The phenomenon – that the male of most higher species of mammal loses interest in specific females after sexual intercourse has taken place – in now universally known as the “Coolridge Effect.”