1903.] Kole of the Blood Fluids in Phagocytosis. 357 



" An Experimental Investigation of the Edle of the Blood Fluids 

 in connection with Phagocytosis." By A. E. WEIGHT, M.D., 

 late Professor of Pathology, Army Medical School, Netley, 

 Pathologist to St. Mary's Hospital, W., and STEWART E. 

 DOUGLAS, M.B.C.S., Captain, Indian Medical Service. 

 Communicated by Sir JOHN BURDON SANDERSON, Bart., 

 F.K.S. Eeceived September 1, 1903. 



It is still a matter of uncertainty whether the blood fluids perform 

 any rdle in connection with phagocytosis. 



Certain facts suggest that the role of the blood fluids, if it comes 

 into consideration at all, is very subordinate. The facts we have 

 in view are, on the one hand, the facts brought forward by Metchnikoff 

 to show that bacteria may be ingested in the living condition, and on 

 the other hand those, brought forward by one of us in conjunction 

 with Captain F. Windsor, I. M.S.,* which show that the human serum 

 exerts absolutely no bactericidal action on the staphylococcus pyogenes, 

 the micrococcus melitensis and the plague bacillus. 



These facts are, however, not conclusive. They are not inconsis- 

 tent with the idea that the blood fluids, apart from actually killing 

 the particular pathogenic bacteria here in question, may in some way 

 co-operate in their destruction. 



What are required for the resolution of the problem are experi- 

 ments in which the phagocytes are tested apart from the blood 

 fluids. 



The experimental methods which we now pass on to describe enable 

 these crucial experiments to be made. 



Methods of Experimentation. 



We have employed a modification of the method of measuring the 

 phagocytic power of the blood, which was devised by Major 

 W. B. Leishman, K.A.M.C.t 



In the procedure described by this author equal volumes of- a 

 bacterial suspension of appropriate density and of blood drawn from 

 the finger are measured off in a capillary tube, mixed on a slide and 

 covered in with a cover-glass. The blood and bacterial culture are 

 then left in contact for 15 minutes in an incubator standing at blood 

 heat. After this interval the cover-glass is, if necessary, loosened 

 from the slide by a drop of physiological salt solution, and the slide 

 and cover-glass are drawn apart by a sliding movement. 



* Wright and Windsor, ' Journal of Hygiene,' vol. 2, No. 4, Oct., 1902. 

 f ' Brit. Med. Journ.,' Jan. 11, 1902. 



