JOHANNESBURG, South Africa, Aug. 10 (UPI) -- South African researchers announced they found cannabis residue on pipe fragments found in William Shakespeare's garden.
Francis Thackeray, an anthropologist at Johannesburg's University of the Witwatersrand and the lead author of the study published in the South African Journal of Science, said he and his team used gas chromatography mass spectrometry to analyze residue found on 24 pipe fragments from the bard's hometown of Stratford-Upon-Avon, England, and cannabis residue was discovered on four fragments taken from Shakespeare's garden.
The team said cannabis residue was found on four other fragments excavated from elsewhere in the town and evidence of Peruvian cocaine was found on two other pipes that were not discovered on Shakespeare's property.
All of the pipe fragments were more than 400 years old, dating from around the playwright's lifetime. The items studied by the researchers were on loan from the Shakespeare Birthplace Trust.
The study called on critics of the theory to reexamine their position in light of the new findings.
"Literary analysis and chemical science can be mutually beneficial, bringing the arts and the sciences together in an effort to better understand Shakespeare and his contemporaries," the study reads.