"Hokey pokey penny a lump, The more you eat the more you jump-"
Anglo-Italian ice-cream vendor
Permission Granted by Copyright Owner for Use on Book DrumAnglo-Italian ice-cream vendor - Credit: Candida Martinelli

'Hokey-pokey' was an American term for ice-cream, and particularly for cheap, inferior brands often sold on the streets by Italian vendors.  The rhyme which Fevvers recites was taken up by 'hokey-pokey' men, who called it out as they walked the streets in a precursor to today's electronic ice-cream van jingles.  

The rhyme passed from the USA to Britain and is part of a repertoire of well-known playground rhymes surviving from the Victorian era.  A variant, perhaps created by children envious of others' ice-cream, ran 'hokey pokey penny a lump, the more you eat the more you pump'.