Ira Remsen (1846-1927), US chemist and discoverer of saccharin. Remsen qualified as a physician in the USA before studying chemistry in Germany. On his return to the USA he introduced the rigorous and professional chemistry that he had learnt in Germany. He translated German books, published his own, and founded the American Chemical Journal. In 1879, after realising that the chemical residue on his fingers tasted sweet, he and his student, Constantin Fahlberg, investigated the residue and found that it was a compound that was 500 times sweeter than sugar. Fahlberg named it saccharin and patented it. This photograph is from a glass negative. It was created in New York by the Pach Brothers, and dates to 2 October 1909. It is now part of the George Grantham Bain Collection.