IMMUNITY. 



has shown that they may be in part nucleins. He has found 

 that blood-serum contains nuclein and that nuclein has 

 germicidal power. Such substances apparently serve as 

 safeguards to the body against all kinds of bacterial in- 

 vasion. They have not necessarily a specific action as 

 regards any particular kind of infection. 



It now appears that the bactericidal power of blood-serum 

 also depends in a large measure upon the joint operation of 

 complements and intermediary bodies. 



The amount of intermediary body appears to be more 

 constant than that of the complement. Flexner 1 found 

 that the blood-serum from cases of chronic diseases had 

 diminished bactericidal power for the staphylococcus pyo- 

 genes aureus. His observations were regarded as explain- 

 ing the liability of these patients to terminal infections. 

 (See page 169.) Longcope 2 has since shown that in such 

 affections as chronic nephritis, cirrhosis of the liver and 

 diabetes the complement, active in destroying bacteria, is 

 diminished. Abbott and Bergey 3 proved that the comple- 

 ment active in disintegrating the blood-corpuscles of another 

 species is reduced in quantity by alcoholic poisoning. Their 

 conclusions are important taken in connection with Abbott's 

 previous work on the effect of alcohol in lowering the re- 

 sisting power to infection (see page 166). 



Agglutinins. 4 It has been shown that the blood-serum 

 of patients having typhoid fever contains a substance which, 

 when mixed with living typhoid bacilli, causes them to 

 gather into groups or clumps and at the same time to lose 

 their motility. In the great majority of cases no such 

 clumping occurs when the blood of typhoid cases is mixed 



1 Journal of Experimental Medicine, Vol. L, 1896, p. 21. 



2 University of Pennsylvania Medical Bulletin, November, 1902, p. 331. 



3 University of Pennsylvania Medical Bulletin, Aug.-Sept., 1902, p. 186. 



4 Sailer, University of Pennsylvania, Medical Bulletin, Aug.-Sept., 

 1902. 



