SIGNIFICANCE OF ALLERGY 539 



Rich, and their respeK'tive colleagues, as well as a number of other 

 investigators, certain factors of primary importance can be deter- 

 mined. Cannon et al., working with staphylococci, and Rich et al., 

 stiidying dermal pneumonia in rabbits, report that when virulent 

 organisms are introduced into the tissues of normal animals they 

 not only undergo multiplication but are disseminated rapidly to 

 various places remote from the point of inoculation. In immune 

 animals the organisms remain localized althougli a certain amount 

 of multiplication occurs. Apparently the presence of antibodies 

 in the tissues causes the organisms to grow in chains or in clus- 

 ters in the manner analogous to that observed in culturas grown 

 in immune serum. The organisms not only tend to adhere to 

 each other but they also stick to the tissue cells. Rich says that 

 such phenomena may be observed before evidence of inflamma- 

 tion appears. He challenges the concept of Zinsser, Krause and 

 many others that acquired resistance is due largely lo allergy 

 and the allergic inflammatory response. Rich grants that the 

 pouring out of an inflammatory exudate after the bacteria have 

 been localized is of value in diluting toxins or toxic substances, 

 and that neutrophiles and macrophages aid in destroying and 

 removing bacteria, but he regards acquired resistance as consist- 

 ing mainly of two factors : ( 1 ) the mechanism by which the or- 

 ganisms are retained at the point of entry and (2) the creation 

 of an environment in which they are less able to survive than 

 in the normal animal. He and his colleagues have shown that 

 rabbits passively immunized to type I pneumococcus are highly 

 resistant but not allergic to the organisms. As a result of this 

 and other experimental studies he concludes that bacterial al- 

 lergy and immunity can be definitely separated from each other. 

 He and McCordock feel that this is especially true in human 

 tuberculosis largely for the following reasons : 



1. Krause and Willis planted tubercle bacilli into areas of 

 tuberculin allergic inflammation and observed that the organ- 

 isms did not remain localized. The results led them to conclude 

 that immunity is reduced at the site of an inflammatoi'y tuber- 

 culin reaction for at least four days. 



2. Immunization with dead tubercle bacilli produced an in- 

 tensive allergic state but only moderate immunity. Petroff and 



