Green’s Dictionary of Slang

catch ’em-alive n.

1. a trap; occas. attrib.

[UK]Hotten Sl. Dict.
[UK]Wild Boys of London I 248/1: I hopes, when I next sees yer, I shan’t have to find yer by going down a patent catch-’em-alive cupboard.
[UK]Farmer & Henley Sl. and Its Analogues.
[Aus]Crowe Aus. Sl. Dict. 16: Catch em Alive, sugared-paper to catch flies.
[UK]Sporting Times 25 Feb. 5/2: Free fishers went sailing out on to the ‘Bank,’ / To the ‘catch-’em-alive,’ as the sun went down; / Each thought of the beauties who’d lay in the tank, / And the ‘stuff’ they would barter for, many a crown.

2. a tooth-comb.

[UK]Hotten Sl. Dict.
[UK]Farmer & Henley Sl. and Its Analogues.