Botulinum toxin
In 1895 (seventy-five years later), Émile van Ermengem, professor of bacteriology and a student of Robert Koch, correctly described "Clostridium botulinum" as the bacterial source of the toxin. Thirty-four attendees at a funeral were poisoned by eating partially salted ham, an extract of which was found to cause botulism-like paralysis in laboratory animals. Van Ermengem isolated and grew the bacterium, and described its toxin, which was later purified by P Tessmer Snipe and Hermann Sommer.
Alexandre Yersin
Yersin was born in 1863 in Aubonne, Canton of Vaud, Switzerland, to a family originally from France. From 1883 to 1884, Yersin studied medicine at Lausanne, Switzerland; and then at Marburg, Germany and Paris (1884–1886). In 1886, he entered Louis Pasteur's research laboratory at the École Normale Supérieure, by invitation of Emile Roux, and participated in the development of the anti-rabies serum. In 1888 he received his doctorate with a dissertation titled "Étude sur le Développement du Tubercule Expérimental" and spent two months with Robert Koch in Germany. He joined the recently created Pasteur Institute in 1889 as Roux's collaborator and discovered with him the diphtheric toxin (produced by the "Corynebacterium diphtheriae" bacillus).