The documents to which this comes from are the Notes & Queries of 1850 & 1851.
The following is just a small part of a dialogue taking places between subscribers to this publication.
In particular it is entitled 'Replies' - COCKNEY (Vol. iv., pp. 273.318)
The following passages collected from various sources will perhaps help to illustrate the origin and the several meanings of this word Cockney: -
Fuller's first sense is:-
"One coaks'd or cockered, made a wanton or nestlecock of, delicately bred and brought up, so that when grown men or women they can endure no hardship, nor comport with pains taking"
" 'Tis not their fault, but our mothers', our cockering mothers, who for their labour make us to be called Cockneys." - Dekker, A Knight's Conjuring. 1607
"And when this jape is told another day"
"I shall be halden a daffe or a Cockenay" - Chaucer, The Reve's Tale .............