A tract-distributor.
»She lammed in tracts at him full of the most awful language». (Sketches 200. 25.)
Old woman of the working class.
Lamb (vulgarized: lam) is sometimes ironically used to indicate a rough, cruel, or merciless person, and thence specifically applied to bludgeon men at elections. To this word we must refer, I suppose, the vulgar verb to lamb or to lam = to beat, to strike frequently. (Figurally or literally.)
The sense of the two above expressions is:
(1) go at him (figurally);
(2) she aimed mental blows at him by means of tracts.
let on
»Don’t let on to any of the chaps that I am a member of that blessed waxwork show». (Novel Notes 203. 20.)