While upon the subject of the treatment of pneumonia, the experiments of Prof. Emmerich of Munich, relating to the production of an artificial immunity against this disease and to curing the same, should be noticed. Emmerich has just reported his experiments before the late Congress of Hygiene and Demography in London.
From previous experiments Emmerich has been led to believe that immunity against infectious disease is produced by a toxine inimical to bacteria, but innocuous toward the cells of the animal body. In an immune animal, at least soon after immunity has been produced, this substance should be found in its blood and other tissue fluids.
By subjecting a rabbit to an intravenous injection of a very dilute but completely virulent culture of the diplococcus pneumonia Fränkeli it is rendered immune. Rabbits so prepared were killed, skinned, divided and rubbed up into a fine paste, which was pressed through the
IMMUNITY AGAINST CROUPOUS PNEUMONIA.. JAMA. 1891;XVII(11):418-419. doi:10.1001/jama.1891.02410890036008