IMMU^aiTY AGAiysr BACTEIilAh ES/AMEfi 117 



cocci digest proteins of exudates feebly, staphylococci more rapidly, 

 and colon bacilli are still more active. He could find no relation 

 between the proteolytic power of the bacteria and the severity of the 

 infection from which they came. Staphylococci can cause coagula- 

 tion of pla.sma and then dissolve the coagulum, showing the presence 

 of two enzymes, staphylokiimse and fihrinolysin (Kleinschmidt).^^ 

 Sperry and Rettger,"* however, found that even the most actively 

 putrefactive bacteria are unable to attack or grow upon carefully 

 purified proteins, although the presence of small amounts of peptone 

 or other available nutrient makes the proteins available to the bac- 

 teria; apparently they must have some nutrient more available than 

 intact protein molecules to enable them to grow sufficiently to produce 

 enough free enzymes to attack the proteins. By virtue of their pro- 

 teolytic enzymes, filtrates of bacteria that liquefy gelatin also can 

 digest hardened liver, kidney and other tissue elements in vitro, the 

 changes resembling those of necrobiosis.^-^ 



Catalase is demonstrable in bacteria, the anaerobic forms showing 

 the least activity (Rywosch),^^ but practically no species is entirely 

 inactive ( Jorns) ; ^* it may exist as either endo- or ecto-enzyme. Cer- 

 tain bacteria and actinomyces exliibit oxidative effects, resembling 

 tyrosinase, but such an enzyme could not be extracted by Lehmann 

 and Sano.^^ 



Immunity against bacterial enzymes may be secured as it is against 

 other enzymes. Abbott and Gildersleeve ^* found that by injections 

 into animals of proteolytic bacterial filtrates which were only slightly 

 toxic, the serum of the animals acquired a slight but specific in- 

 crease in resistance to the proteolytic enzymes of the filtrates.^^ 

 Normal serum contains a certain amount of enzjTne-resisting sub- 

 stance. Other observers have found that immunization against living 

 or dead bacteria leads to the production of substances antagonistic 

 to their enzj-mes, but the degree of resistance acquired is never 

 great, v. Dungern ^' found that the serum of animals infected with 

 various bacteria prevented digestion of gelatin by the enzymes ob- 

 tained from cultures of the same species of bacteria. He applied 

 this fact to the diagnosis of infectious conditions, finding that the 

 serum of a patient with osteomyelitis was over twenty times as 

 strongly inhibitory to staphylococcus enzymes as was serum of nor- 

 mal persons. The reaction is specific, cholera vibrio enzjTiies not be- 

 ing inhibited to any corresponding degree. 



52Zeit. Immunitat., 1900 (3). 516. 

 52a .Jour. Biol. Chem., 1915 (20), 445. 

 52bBittrolff. Ziegler's Bcitr., 1915 (60), 3.37. 



53 Cent. f. Bakt., 1907 (44), 295. 



54 Arch. f. Hvcr., 1908 (67), 134. 



55 Arch. f. Hyg., 1908 (67), 99. 



56 Antigelatinase has also been obtained bv Bertiau. Cent. f. Bakt., 1914 (74), 

 374. 



57 Munch, med. Woch., 1898 (45), 1040. 



