The poem
'A shilling's worth of quinine, please,' The customer demanded. The druggist went down on his knees And from a cupboard handed The waiting man a tiny flask: 'Here, Sir, is what you ask.'
The buyer paid and went away, The druggist rubbed his glasses, Then sudden shouted in dismay: 'Of all the silly asses!' And out into the street he ran To catch the speeding man.
Cried he: 'That quinine that you bought, (Since all may errors make), I find was definitely not,-- I sold you strychnine by mistake. Two shillings is its price, and so Another bob you owe.'