PASTEUR LOUIS: (1822-1895) French chemist and microbiologist, renowned for his discoveries of the principles of vaccination and pasteurisation. A good L.S., L. Pasteur, two pages, 8vo, green paper, Villeneuve l´Etang, Seine et Oise, 21^st July 1888, to a colleague, in French. On his personal printed stationery bearing a green embossed monogram with his initials, Pasteur asks for advice on a delicate matter, and expecting that his correspondent will meet his son-in-law to deal about it, states in part `J´ai le plus vif désir d´avoir de vous un conseil dans une affaire delicate. Mon gendre Vallery-Radot est, vous le savez, exécuteur testamentaire de M. Chantelauze qui a légué à l'Institut une collection précieuse de livres et de manuscrits sur l'histoire de la Fronde et le cardinal de Retz... L'exécution du testament offre des difficultés qui durent depuis 6 mois. Mr. Vallery-Radot vous les expliquera et je vous serai très reconnaissant de vouloir bien lui accorder quelques minutes d´entretien le plus tôt qu´il vous sera possible´ (`I have the strongest desire to have some advice from you about a delicate matter. My son-in-law Vallery-Radot is, as you know, executor of Mr. Chantelauze who bequeathed to the Institute a valuable collection of books and manuscripts on the history of the Fronde and Cardinal de Retz... The execution of the will offers difficulties that have lasted for 6 months. Mr. Vallery-Radot will explain them to you and I would be very grateful if you would grant him a few minutes of your time as soon as possible´) The present letter was written only few months before the opening of the Pasteur Institute. With blank integral leaf. Extremely small tear to the upper edge, otherwise G