French physiologist (1850–1935) who won the 1913 Nobel Prize in Medicine for his work in anaphylaxis, which led to advances in the treatment of allergies. ALS, one page, 5 x 8, personal letterhead, no date. Richet writes to M. Halpérine. In part (translated): “I have indeed received a letter from Count L. Tolstoy’s son and I have sent him the books on hygiene he requested….” Accompanied by the original mailing envelope. Mild soiling and wrinkling, otherwise fine condition. R&R COA.