SERUM ENZYMES 525 



them there chiefly from the point of view of their phagocytic and 

 antibacterial functions. It will be useful to consider at a little 

 greater length the importance of these cells from the point of view 

 of purely enzymotic activity. 1 



As early as 1885 Hammarsten called attention to the fact that 

 leucocytes aid in dissolving fibrin. Leber 2 subsequently studied pus 

 and found that it possessed a powerful digestive action for gelatin, 

 fibrin, and other protein substances. He correlated his studies par- 

 ticularly with the processes of inflammation, and his work, as well 

 as that of later investigators, brought into the foreground the fact 

 that in the resolution of abscesses, especially of the staphylococcus 

 variety, the leucocytes might play an important role in liquefying 

 the necrotic tissue cells and bringing about the breaking down of 

 the center of the abscess. Any one who has carefully studied the 

 histology of a staphylococcus abscess can easily see the halo of disin- 

 tegrating tissue lying just inside the ring of aggregated polymorpho- 

 nuclear leucocytes. That these cells carry on an important part in 

 this liquefaction is certain, although as yet we are not sure whether 

 or not the proteolytic bacterial enzymes participate. Friedrich Miil- 

 ler, 3 in 1902, also studied these processes and gave clinical signifi- 

 cance to the proteolytic activities of the white blood cells in the 

 resolution of the pneumonic lung. The study of inflammatory exu- 

 dates by Opie 4 confirmed much of the preceding work and revealed 

 that the ferments of all white blood cells were not the same. He 

 found a leucoprotease which was contained in the polynuclear leuco- 

 cytes which was active chiefly in a slightly alkaline medium, whereas 

 the large mononuclear cells of uncertain origin which appear toward 

 the end of an inflammatory process contained a protease which was 

 active in weak acid. This differentiation of a leucoprotease and a 

 lymphoprotease was more or less confirmatory of assumptions made 

 earlier by Metchnikoff. It seemed probable that the acid protease 

 noticed by Opie is specific to the large mononuclear cells of such 

 exudates and is not common to lymphocytes in general, for the con- 

 sensus of opinion of other workers seems to be that the small lympho- 

 cytes contain no proteolytic enzyme whatever. The study of tubercu- 

 lous exudates particularly has failed to reveal proteolytic properties 

 when only the characteristic small lymphocytes were present, al- 

 though some writers, Bergell 5 especially, have shown that these cells 

 contain a fat-splitting enzyme. Such lipase could also be determined 

 in the press-juice of lymphoid organs, such as the spleen and lymph 

 nodes. It is not improbable that the characteristic dry abscess or 



1 See Wiens. Ergebnisse d. Allg. Pathol. Lubarsch & Ostertag, Vol. 15, 

 1911. 



2 Leber. Entstehung der Entzundung. Leipzig, 1891. 



3 Fr. Miiller. Verh. d. 20 Kongress f. innere Mediz., Wiesbaden, 1902. 



4 Opie. Journal of Exp. Med., Vols. 7 and 8, 1905 and 1906. 



5 Bero-ell. Munch, med. Woch., 1909. 



