Experimental Pathological Studies on the Nature and Rôle of Bacterial Allergy.

It is now well known that while the body is acquiring an active immunity to bacteria during infection, the tissues ordinarily become hypersensitive to the protein of the infecting microorganisms. When this hypersensitiveness has appeared, the tissues will be locally damaged and killed by amounts of the bacterial protein which are harmless to the normal body, and disturbing constitutional symptoms and even death may occur when amounts of the protein which would be harmless to the normal body find their way into the blood stream of the hypersensitive one. By the side of this hypersusceptibility of the tissues to the protein of the infecting bacteria there is also developed a heightened resistance to the growth of the bacteria, and their spread through the tissues and into the blood stream is markedly inhibited. The state of hypersusceptibility to the bacterial protein is ordinarily spoken of as allergy; the ability of the body to inhibit the growth and the invasion of the bacteria, and to neutralize the toxins which they may produce, constitutes acquired immunity.