Mostly letters from ex-patients to Platt thanking him for treating them when they were children and in some cases reminiscing about their time in hospital. Some include replies from Platt, who often investigated his case notes and operation books regarding the patient. Platt has annotated a number of the letters. Platt sometimes used information given by patients on their current health to update his follow-up files on survival (see Records of Orthopaedic Practice (PLA/1)). Sometimes information has been sent by doctors about Platt's ex-patients.
See also files of letters of birthday congratulations from ex-patients on Platt's 90th and 100th birthdays, PLA/13/9/3/2 and PLA/13/9/4/3.