The peko-peko's skin is toxic, and most predators leave it alone. Sentient hunters prey on the peko-peko to harvest the amazing anti-venin the animal secretes.
医学百科 The Medicine Book (Big Ideas Simply Explained)
Ehrlich theorised that the antitoxins involved in this immune response were chemical receptors or side-chains attached to cells, just like the structures he had observed on dyes.
医学百科 The Medicine Book (Big Ideas Simply Explained)
In 1890, German physiologist Emil von Behring and Japanese physician Shibasaburo Kitasato discovered that antitoxins made by the body in response to a pathogen could be used to prevent disease.