JOHN BRAY was one of Hillingdon’s finest detectives, helping identify a killer that had been stalking us for years.

The young doctor arrived at Hillingdon Hospital in 1938, expecting to examine civilian casualties from German bombing raids.

Instead, he found an equally dangerous adversary waiting for him.

Infant cholera - more commonly known as gastro-enteritis - claimed the lives of 20 babies between March 1943 and April 1944.

It was a ‘disease of theories’ whose culprit had confounded a succession of experts, including the great Louis Pasteur.

Bray’s first clue came when a fellow doctor told him he always knew a child had gastro-enteritis before examining them.

“How?” asked Bray “They have a funny smell,” replied his colleague.

Bray returned to his laboratory and noted a culture plate infected with gastro-enteritis had the same distinctive smell.

He began using his nose to sniff out the elusive germ, naming the infected culture plates used to test bacterial infections as ‘smellers’.

He added another piece to the puzzle by discovering the mystery germ grew in a particular sugar solution, but his evidence remained flimsy.

Bray enlisted the help of pet rabbit Snowy, who was injected with infected material - animals are immune to gastro-enteritis - and an anti-serum was created from its blood.

So began a long process of trial and error as the anti-serum was tested on a large collection of cultures collected from children and adults who had and had not been diagnosed with gastro-enteritis.

Bray would wrestle with the problem for four years and later wrote: “I felt, with despair, that I was deluding myself and not on the right track at all. A feeling, I think, not rare in research of this kind.”

In reality, the answer was in plain sight but blinded by the long-held medical belief that pink-coloured colonies of intestinal bacteria were harmless, compared to dangerous white colonies, like salmonella and dysentery.

In reality, Bray’s adversary was a pink wolf in sheep’s clothing.

He published his results in 1945, including a test that could differentiate between simple digestive upsets and the disease-carrying version of the bacteria e.coli.

Medical experts around the world remained sceptical, despite the editor of the Journal of Pathology and Bacteriology believing his author had made a major discovery.

A number of curious pathologists took note and, following Bray’s lead, succeeded in isolating and identifying the germ.

The Hillingdon doctor’s quiet determination had finally paid off and, with it, the satisfaction that his discovery would save countless young lives across the world.