88 ENZYMES 



importance in producing shock whenever tissues are injured.^ Methyl 

 guanidine may also be formed from disintegrating tissues and has con- 

 siderable toxicity. 



Work has been reported upon autolytic processes in a number of 

 pathological conditions, which may be discussed briefly as follows: 



Exudates. — The presence of leucine, tyrosine, proteoses, and pep- 

 tones in pus has been known for many years, and the reason for their 

 appearance is now clear. Muller,^ many years ago, observed that 

 purulent sputum digested fibrin, but that non-purulent sputum did 

 not have this property. Achalme^ found that pus would dissolve 

 gelatin, fibrin, and egg-albumen. Ascoli and Mareschi^ detected 

 autolysis in sterile exudates obtained experimentally. Umber^ found 

 that ascitic fluid exhibited autolytic changes, which observation 

 could not be confirmed by Schiitz^ in pleural exudates and ascitic 

 fluids. Zak^ found that autolysis was inconstant in various exudates. 

 The differences in these results are explained by Opie's^ observation 

 that in experimental inflammatory exudates the leucocytes are capable 

 of marked autolysis, whereas the serum contains an antibody which 

 holds this autolysis in check; if the antibody is destroyed by heat, then 

 the serum proteins are also digested by the leucocytic enzymes. This 

 antibody seems to be contained normally in the albumin of the 

 blood-serum. In old exudates the antibodies are decreased, and auto- 

 lysis then occurs, explaining the variable results of Umber, Schiitz 

 and Zak. The intracellular proteases of the polynuclear leucocytes 

 act best in an alkaline medium; those of the mononuclears in acid 

 medium. If the proportion of serum to leucocytes is high, then there 

 is no autolysis, as in serous exudates; but if the leucocj^tes are abun- 

 dant, then the antibody is overcome and we get autoh'sis, as in ordinary 

 suppurative exudates. Animals with but little protease in their 

 leucocytes (e. g., rabbits), do not ordinarily produce a liquid pus (Opie). 

 Exudates produced by bacterial infection also seem to possess the 

 properties above described. Galdi^" found autolysis greater in exu- 

 dates than in transudates, but observed no constant relation between 

 the number of leucocytes, or the amount of chlorides, and the rate of 

 autolysis. All exudates, according to Lenk and Pollak,^^ contain 

 enzymes splitting glyeyl-glycinc (peptolytic enzymes); the most active 



2 See Abel and Kubota, Jour. Pharm. Exp. Ther., 1919 (13), 243. 



3 Kossel, Zeit. f. klin. Med., 18S8 (13), 149. 

 ^ Compt. Rend. Soc. Biol., 1899 (51), 568. 



6 See Maly's Jahresbericlit, 1902 (32), 5(38. 

 6 Munch, nied. Woch., 1902 (49), 11(59. 

 'Cent. f. inn. Med., 1902 (23), ll(il. 



8 Wien. klin. Woch., 1905 (18), 37(j. 



9 Jour, of Exper. Med., 1905 (7), 310 and 759; 190(i (8), 410 and 530; 1907 

 (9), 207, 391 and 414; also a full review in Arcii. Int. Med., 1910 (5), 541. 



'0 See Folia Ilcinat., 1905 (2), 529. 



'» Dcut. Arcli. klin. Med., 1913 (109), 350; See also Wiener, liiocliein. Zeit., 

 1912 (41), 149; Al!iiid<'ll)auiii, Miinch. lued. Woch., 1914 ((il), 4()1. 



