128 Dr. A. E. Wright and Capt. S. E. Douglas. [Jan. 11, 



" Further Observations on the Hole of the Blood Fluids in con- 

 nection with Phagocytosis." By A. E. Weight, M.D., late 

 Professor of Pathology, Army Medical School, Netley, 

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

 Douglas, M.E.C.S., Captain, Indian Medical Service. Com- 

 municated by Sir J. Burdon Sanderson, F.E.S. Eeceived 

 January 11, — Eead February 25, 1904. 



(From tlie Pathological Laboratory of St. Mary's Hospital, London, TV.) 



[Plate 3.] 



In a previous communication we showed that the phagocytosis which 

 occurs when cultures of the Staphylococcus pyogenes are added to 

 human blood, is directly dependent upon the presence of certain 

 substances in the blood which exert a specific effect upon the bacteria. 

 We suggested that the bacteriotropic substances here in question 

 might appropriately be denoted by the term " opsonins." 



In the present paper we propose to bring out certain further points 

 in connection with the " opsonic power " of the blood. 



Eelation of the Opsonic Power of Human Blood to the 

 Capacity of Resisting Invasion by the Staphylococcus 

 Pyogenes. 



It has already been shown* by one of us that patients who are the 

 subjects of acne, sycosis, or boils are characterised by a defective phago- 

 cytic power for the Staphylococcus pyogenes. We have recently been 

 able to satisfy ourselves that this defective phagocytosis is dependent 

 upon a defect of opsonic power. 



It has also been shown by one of us that the cure of these bacterial 

 infections, which can in almost every instance be achieved by the 

 inoculation of appropriate quantities of sterilised staphylococcus 

 cultures, is associated with the acquirement of an increased phagocytic 

 power. We have now succeeded in establishing the fact — already 

 adumbrated in our previous paper — that the increased phagocytosis 

 which is associated with the achievement of the condition of immuni- 

 sation here in question is dependent, not upon a modification of the 

 white corpuscles, but upon a development of opsonins in the blood 

 fluids. 



The results of the subjoined experiment bring out this fact into clear 

 relief. 



Details of the Experiment. 



Immunised Patient's Blood. — The patient, F. F., who had long been the 

 subject of aggravated staphylococcic sycosis, had, after prolonged and 

 * ' Lancet,' March. 29, 1902. 



