Unknown letters of the professor S.S. Yudin are presented in the article, written by him at period of the reference in Berdsk. They are addressed to its colleague in the Institute to ambulance named after the N.V. Sklifosovskiy. The authors give the estimation epistolary heritage known surgeon, considering its as important source on study of the histories to domestic surgery. The noted role of the museum of clinical institution in conservation and presentations society monuments of the medical science.