256 IXFLAMMATIOX 



has been able to extract from the bodies of protozoa (rhizopods) a 

 feebly proteolytic enzyme. This "atnibodiastase," as he calls it, is 

 active in alkaline, and faintly acid media, and digests colon bacilli that 

 have been killed by heat, but not living bacilli. This last fact is 

 highly suggestive in connection with the important question of whether 

 leucocytes engulf and destroy virulent bacteria or only those that have 

 been previously injured by the tissue fluid. It was impossible to se- 

 cure either invertase or lipase in extracts of protozoa. Whether bac- 

 teria are digested in leucocytes by the same enzymes that digest the 

 leucocytes themselves after they are killed (?'. e., the autolytic fer- 

 ments), or by some specialized enzyme is not known. Metchnikoff, 

 however, has noted the localized production of acid in the cytoplasm 

 of leucocytes of the larva of Triton taeniatus. The eventual excre- 

 tion of the remains of the bacteria or other foreign bodies by the 

 phagoc3^tes is ascribed by Rhumbler to changes in the composition of 

 the particles through digestion, so that they have a greater surface 

 affinity for the surrounding fluids than for the protoplasm of the cell. 

 Calcium and magnesium salts increase phagocytosis and leucocytic 

 migration, ^<^ while changes in osmotic pressure decrease these activi- 

 ties, as also does quinine even in dilutions of 0.001 per cent. Phago- 

 cytosis cannot take place in the absence of elect rol3'tes, according to 

 Sawtchenko.^^ Fat-soluble substances in general increase phagocyto- 

 sis (Hamburger),^- but cholesterol inhibits phagocytosis.^^ (its ef- 

 fects being suppressed by lecithin) ^^ acting apparent I3' by virtue of 

 its OH group. Agents facilitating oxidation favor phagocj'tosis 

 (Arkin).^^ Maximum phagocytosis occurs at the normal bodj^ tem- 

 perature of the animal furnishing the leucocytes (Madsen and Wulf' .'^ 

 Phagocytosis cannot be readil}- ascribed to chemotaxis, however, 

 in the case of phagocj^tosis of perfectly' insoluble, chemicalh' inert par- 

 ticles, such as coal-dust. The leucocytes seem to take up foreign 

 bodies without reference to their nutritive value, absorbing India-ink 

 granules and bacteria impartially when they are injected together, 

 and loading themselves so full of carmine granules that they cannot 

 take up bacteria subsequent!}- injected. It is possible that foreign 

 bodies first become coated with a layer of altered protein which then 

 leads to phagocytosis, but there is no sufficient evidence for this sur- 

 mise. Kite and Wherry^^ state that leucocytes take up car])on parti- 



*" Hamburger, Biochem. Zeit., 1910 (26), GO; Eggers, Jour. Infect. Diseases, 

 1909 (6), 662. According to Radsma (Arcli. neerl. pliysiol., 191S (2), .301) cal- 

 cium salts only favor phagocytosis in leucocytes that have previously had their 

 calcium l)oun(l by citrate or oxalate in the ])rocess of isolation. 



"Arch. .sci. Inol. 8t. IVtershurg. 1911 (1(1), UH ; 1912 (17), 12S. 



" Hamburger and de llaan, Arch. .\na(. und Phv.sio!., 19i;J, I'hys. .Vbt., p. 77 



" Dewey and Nuzum, .Jour. Infect. I)is., 1914 (if)), 72. 



'■'Htuber, liiochem. Zeit., 1913 (51), 211; 1914 ('>;{), 493. 



"Jour. Infect. Dis., 1913 (13), 41S. 



"Over, Dan.ske Vid. Selsk. Forh., 191t) ((>), 339. 



" Jour. Infect. Dis.. 191.") (Ki), 109. 



