Passage: Prof Charles Robert Richet (25 August 1850 – 4 December 1935) was a French physiologist at the Collège de France known for his pioneering work in immunology. In 1913, he won the Nobel Prize in Physiology or Medicine "in recognition of his work on anaphylaxis". Richet devoted many years to the study of paranormal and spiritualist phenomena, coining the term "ectoplasm". He also believed in the inferiority of blacks, was a proponent of eugenics and presided over the French Eugenics Society towards the end of his life. The Richet line of professorships of medical science would continue through his son Charles and his grandson Gabriel. Gabriel Richet was one of the great pioneers of European nephrology.

Question: Charles Robert Richet was most recognized for waht in 1913?
his work on anaphylaxis