throw in the bark

From the fact that the bark of the cinchona tree is used to make the medicine quinine.

throw in the bark (third-person singular simple present throws in the bark, present participle throwing in the bark, simple past threw in the bark, past participle thrown in the bark)

1. (obsolete, medicine) To administer quinine.
   • 1749, Henry Fielding, chapter IX, in The History of Tom Jones, a Foundling, volumes (please specify |volume=I to VI), London: A[ndrew] Millar, […], →OCLC, book V:

     The physician dined that day at Mr Allworthy's; and having after dinner visited his patient, he returned to the company, and told them, that he had now the satisfaction to say, with assurance, that his patient was out of all danger: that he had brought his fever to a perfect intermission, and doubted not by throwing in the bark to prevent its return.

   • 1790, William Buchan, Domestic medicine: or, A treatise on the prevention and cure of diseases, 11th edition, page 151:

     In intermitting fevers of an obſtinate nature, I have found it necessary to throw in the bark much faſter.

   • 1864 (Nov 5), E. Hare, "The treatment of malarious fever", The Medical Times and Gazette, Volume 2, page 487

     An emetic was prescribed, a perspiration broke out, and I now, with an air of confidence, began to throw in the bark, quite sanguine in my expectations of soon checking this formidable disease.