Devoted owners have long suspected (怀疑) that man’s best friend can do more than just wag its tail or fetch sticks.
Now, it seems dogs can be trained to detect cancer－by sniffling their owners’ urine (尿).
Scientists found that a selection of pet dogs recognized patients with bladder cancer (膀胱癌) nearly three times more often than would be expected by chance.
The dogs even picked up a kidney tumour (肾肿瘤) in a patient who was not known to have the disease and which had been missed in two scans (扫描). A surprised advisor ran a third test and proved that he had the disease.
The suggestion that dogs might be able to smell cancer was first made in 1989 by two London dermatologists (皮肤病学家). A woman asked them to cut a mole (痣) out of her leg because her dog constantly sniffled it, even through trousers. One day, the animal tried to bite the mole off when she was wearing shorts.
It turned out she had a deadly form of skin cancer, which was caught early enough to save her life. In the latest study, dogs of different ages were trained for seven months to tell apart between urine from patients with bladder cancer and those without the disease.
Dogs recognize patients with cancer－by lying next to them－41 per cent of times, rather than 14 per cent expected by chance, scientists from Amersham Hosptibal, Buckinghamshire, told British Medical Journal.
1．It is suggested in the passage that dogs recognize patients with cancer mainly ______.
A．by chance
B．by sense of smell
C．with their eyes
D．with their mouths
