The Sir William Osler Collection, distinct from the Bibliotheca, is an extensive archival holding of Osler's correspondence (including eighteen hundred original letters), daybooks, accounts, engagement books, legal documents, book invoices, membership certificates, notebooks, lectures, addresses, newspaper clippings, photographs, books with manuscript additions, and miscellaneous loose items formerly inserted into individual books in his library. The collection also contains various family papers, including correspondence of Lady Grace Revere Osler and Edward Revere Osler.

Letter to Henry R. Viets from William Osler, 13, Norham Gardens, Oxford, Oxfordshire, England. Osler is delighted with the de Cusa treasures Viets has located. He suggests that Viets write the introduction to the translated version of "De Staticis Experimentis."

Letter to Henry R. Viets from William Osler, 13, Norham Gardens, Oxford, Oxfordshire, England. Osler sends Viets the translation of de Cusa's "De Staticis Experimentis." He suggests that Viets consult the new History of Science man at Harvard for more information on de Cusa. He writes that he is better, although he is still in bed and still coughing.

Letter to Henry M. Hurd from William Osler, 13, Norham Gardens, Oxford, Oxfordshire, England. Osler thanks Hurd for sending copies of the "Bulletin." He will send his heart and artery, as well as his Tuberculosis literature to the Johns Hopkins Library. He reports that Cushing has been visiting at Oxford and is in good form.

Letter to Harvey Cushing from William Osler, 13, Norham Gardens, Oxford, Oxfordshire, England. Osler asks for information about Cushing's cases of nerve anastamoses.

Letter to Harvey Cushing from William Osler, 13, Norham Gardens, Oxford, Oxfordshire, England. Arrangements for a publication venture with Clarendon Press. He refers to an outbreak of encephalitis in the U.S. He will serve as the President for the upcoming meeting of the Classical Association.

Letter to Harvey Cushing from William Osler, St. Brelades Bay, Jersey, England. The Oslers are enjoyng their vacation by the sea. Osler extends his sympathies upon the death of Cushing's nephew. He is rewriting sections of his text book and asks Cushing about his experiences with certain medical cases.

Letter to Peyton T. B. Beale from William Osler, 13, Norham Gardens, Oxford, England. In one of his last letters, written from bed, Osler inquires after a 1902 edition of "Religio Medici" that Beale's father published anonymously.