Definition of "rats"

"It's damned clever - fair puzzles 'em every time. How d'ye get them?" "I tell you I don't. It's outside myself." "Rats! You can tell me, Tom. I'm Griffiths, the safe man."

1925 July – 1926 May, A[rthur] Conan Doyle, “(please specify the chapter number)”, in The Land of Mist (eBook no. 0601351h.html), Australia: Project Gutenberg Australia, published April 2019