CHAPTER VIII 

 NATURAL AND IMMUNE ANTIBODIES 



Duriii.u' Iho decade l)elw(H'n 1880 and 1890 two Iheorios arose 

 as to the natui-e of the l)ody's defense against infectious agont.s. 

 The one, under the leadersliip of Fliigge and von Fodor in (iermany 

 and Nnttall in Enoland, conceived of the body's defense as ])eino- 

 due to chemical suljstances in the blood, while the other, under 

 the leadership of IMetchnikoff, maintained tliat when infectious 

 agents entered the l)ody, they were engulfed (phagocytized) by 

 certain wandering and fixed tissue cells and ultinuitely destroyed 

 by a process of digestion. The former is known as tlie humoral 

 theory, while the latter is the cellular theory of immunity. 



The Humoral Theory of Immunity, according to Ledingham, 

 had its origin in Lord Lister's (1880-81) experiments on the 

 keeping quality of aseptically removed ox blood. Blood itself is 

 a complex circulating body fluid which functions as a carrier of 

 oxygen and of the nuti-itive, waste and other materials of the 

 body's metabolism. About 30 to 40 per cent of it is made up of 

 cellular material while the remainder is the fluid portion or plasma. 

 This latter contains 90 to 92 per cent water and 8 to 10 per cent 

 proteins, carbohydrates, fats, electrolytes and a wide variety of 

 substances of unknown structure such as enzymes, antienzymes, 

 antibodies, etc. When blood clots, there is scpieezed out a straw- 

 colored fluid called scruui which differs from plasma in tliat tlie 

 tibrinogen has been removed in the process of clotting. Blood 

 from which fibrinogen has been removed is called defibrinated 

 blood. 



Locke and Hirscii* state (1928) that chemical concepts of im- 

 munity had become sufficiently crystallized by 1887 to lead 

 Emmerich to make the following suggestion : "It should be an 

 important task for investigators to seek out the substances which 

 are associated with tlie inununity state and to ascertain in what 

 chemical grouping they belong."' 



*"The Isolation of Substances with Immune Properties," by A. Locke and 

 K. F. Hir.scb. in The Xetcer Knouledffe of Bacteriology and Immunology, edited 

 by E. O. Jordan and I. S. Falk. Reprinted by permission of the University 

 of Chicago Press. 



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