Ilja Metschnikow 

This black and white portrait of Ilja Metschnikow is a fine example of a portrait photograph by the French photographer Felix Nadar. Nadar was a pioneer in portraiture, known for his innovative techniques and ability to capture the personality of his subjects. This portrait, likely taken towards the end of Metschnikow's life, shows the scientist with a thoughtful expression, his white beard and spectacles adding to the sense of wisdom and intelligence. Nadar's work is characterized by its realism and attention to detail, as evident in the fine texture of Metschnikow's clothing and the subtle lighting that shapes his features.