I once had a primary school teacher who had a unique method of dealing with classroom hygiene. When he detected an unsavoury odour in the room he would direct his ‘trained’ henchmen to move slowly around the classroom sniffing the shoulders of all the pupils. The offending schoolboy would be identified, ‘It’s him Sir!’ and despatched to use the ‘facilities’. How his henchmen, who were fellow pupils, were ‘trained’ I can’t remember, but their sense of smell did seem to be related to the amount of cow-towing and availability of toffee or bulls eyes from potential offenders. A recent report from a team of researchers at Amersham Hospital in Buckinghamshire has offered an altogether more beneficial use for ‘sniffing’. Dermatologist Carolyn Willis and her team have trained six dogs of different breeds to detect the urine of patients with bladder cancer. Dogs are widely recognised for finding smells that humans miss and 15 years ago The Lancet reported the use of sniffer dogs in a melanoma clinic. The Amersham researchers hope their work may lead to the development of early-detection screening methods for bladder cancer – though the possibility of making an appointment to see a dog may be some time away. However there is bad news for dog snobs. It seems that of the six different breeds used in the tests, no one breed outperformed the rest. So perhaps when it comes to sniffing, all dogs are created equal.