Deadly Poem

Ring-a-Ring o'Rosies
A Pocket full of Posies
"A-tishoo! A-tishoo!"
We all fall Down!

A simple children's nursery rhyme with a much more sinister (although some sources point to other interpretations) meaning-the massive deaths from the Bubonic Plagues of the 14th to 17 centuries. 

Ring-a-Ring o'Rosies: represented the blotches and sores of the disease. 
A Pocket full of Posies: was the attempt to ward off the disease by smelling fresh herbs and fragrant flowers to counter the "poisonous vapours." *
"A-tishoo! A-tishoo!": the sneezing that took hold of the victim's in the final stage of the disease.
We all fall Down!: the sick drop dead.

(or is it-Modern revisionists doubt the story while many Old English historians believe it)

Results of the "Black Death" in the 14th century Europe are estimated to be in excess of 25 million in less than five years (1347-1352).  Thus the plague killed a third of the European population in general and more than fifty percent of the people of many communities such as the City of Venice.  So many died that the entire economy and social systems of Europe were radically changed.  The individual was now more valuable as there was often a great shortage of labor. The plague would continue to revisit Europe for the next three hundred years. At its height in the outbreak of 1666, the pandemic was killing more than 5000 people a day just in London. The plague's last great Asian outbreak at the start of the 20th century killed over 10 million alone just in British Colonial India.  The disease is still found throughout the World today, but luckily for all it is treatable with modern medicine.

*The belief that sight and smells could carry and spread the disease led to another saying, "Seeing the World through rose-colored glasses."  Doctors and others would wear a mask that had rose colored glass eyepieces that they believed would prevent them from getting the disease.  As an added protection the nose of the mask would be filled with herbs and sweet flowers to defeat the deadly vapors.  The concept that deadly diseases such as Yellow Fever, Cholera, Malaria and the like were transmitted by "Deadly Vapors" lasted into the early 20th century.