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May 4, 1918


Author Affiliations


From the Memorial Institute for Infectious Diseases.

JAMA. 1918;70(18):1273-1278. doi:10.1001/jama.1918.02600180001001

The study of immunity as manifested by the reactions of the animal body to microbes, toxins and protein materials in general has given us many tests of great value. The phenomena of agglutination, of complement fixation, of altered reactivity, of opsonification and of serum precipitation have all been put to practical use in tests, some of which are used every day throughout the civilized world. Speaking generally, the only way now known to trace protein substances back to their source, that is, to the species from which they come, is by means of their immune reactions; and in the case of blood and other animal products, practically the only method for purposes of biologic differentiation is the precipitin test. Because the determination of the ultimate source of blood spots and stains often is vital to the administration of justice, the precipitin test is of special forensic value and interest, and