IMMUNOCHEMISTRY 



hats" permit a substitution of antibody nitrogen values for mouse 

 protection, and then only in rabbit antisera to certain of the other 

 pneumococcus types. Millions of mice were finally saved, however, 

 from succumbing to protection tests by the advent of sulfa drugs and 

 penicillin, which made antipneumococcus sera practically obsolete. 

 Although large volumes of antipneumococcus horse sera, at least, have 

 enriched the efHuent from certain production centers of biologicals in 

 order to release storage space, infants and children are still being cured 

 ot influenzal meningitis by known amounts of antibody from rabbit 

 antisera to H. influenzae type b (1), for a drug to cure this dread disease 

 has not yet been found,* nor is the mouse protection test free from diffi- 

 culties in both its application and interpretation. 



Combining proportions by weight in the precipitin reaction 

 were studied, and with their aid a quantitative theory of this reaction 

 was derived from the law of mass action, leading to a simple linear 

 relation applicable to many immune systems (12). The data obtained 

 were most easily explicable on the basis of the union oi' multivalent 

 antigen and multivalent antibody, giving concrete and quantitative 

 mathematical expression to the less definite "lattice" or "framework" 

 theory of Marrack (30). 



The assumptions which were made admittedly involved over- 

 simplification, but this seemed pardonable in a pioneer theory which 

 explained much that had appeared mysterious and provided simple, 

 usable equations that could be readily understood. There was time 

 enough for taking care of the complications later, as several friends and 

 colleagues have done. Pauling and his group (33), brushing aside 

 the original assumptions as "arbitrary and unlikely," have made a 

 different application of the laws of chemical equilibrium but arrived at 

 the same approximate equations (were their faces red!). By a sta- 

 tistical approach Kendall (28) has paralleled and outstripped the 

 original theory, once more obtaining equations of the same form for 

 the precipitin reaction and succeeding in explaining quantitatively 

 even the limited range of toxin-antitoxin flocculation. One would 

 like to say more and know more about Hershey's (23) painstaking and 

 rigorous, but painfully complicated, analysis. Boyd (3) has been a 

 consistent Rightist in his attitude toward the theory of mutual multi- 

 valence, holding to the old notion that antigen-antibody combination 

 * Streptomycin shows promise (H. E. Alexander, Science, in press). 



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