Читать книгу The Body at Work: A Treatise on the Principles of Physiology онлайн

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If germs of diphtheria are injected into the blood of a horse, the first injections give rise to marked febrile symptoms. After a number of injections the horse becomes completely tolerant of the virus. Not only does its blood develop sufficient antitoxin to protect it against the toxin of diphtheria, however large may be the quantity injected into its system, but the serum of the prepared horse, when injected beneath the skin of a child suffering from diphtheria, carries with it sufficient antitoxin to destroy the toxin which has gained admission to the child’s blood.

Many more instances might be cited of this capacity of developing “antibodies” of protoplasm. The leucocytes of the blood are incessantly adapting their chemistry to the needs of the economy. All the tissues, it may be supposed, possess the power of developing resistant ferments; but the leucocytes (ssss1) are the undifferentiated cells, the maids-of-all-work. They have not specialized as makers of ptyalin or makers of pepsin. They are not completely given up to lifting weights, like muscles, or carrying messages, like nerves.