2l6 MANUAL OF BACTERIOLOGY. 



On the other hand, Wright and Douglas,* whose results have 

 been corroborated by others, found that certain substances pre- 

 pare the bacteria for the phagocytes. These substances are 

 developed in the blood under certain conditions. Thus, in- 

 jections of dead cultures of the S. pyogenes aureus into the 

 blood produces a substance which prepares the live staphy- 

 lococcus as food for the phagocytes. Substances acting in this 

 way they call "opsonins" (opsono, I prepare victuals for). 



These authors find that phagocytosis for certain organisms 

 depends upon the presence of opsonins in the blood. Thus, 

 B. typhosus, S. choleras Asiaticae, B. coli communis, B. dysen- 

 teriae, S. pyogenes aureus, B. pestis, M. melitensis, D. pneu- 

 monias, are all taken up by phagocytes after being prepared by 

 the opsonins. B. diphtherias and B. xerosis are not acted upon 

 by opsonins. 



Wright speaks of the number of bacteria which may be 

 counted inside of the leukocytes on an average as the "opsonic 

 index," and he uses so-called vaccines derived from cultures 

 with the purpose of increasing this index. There is wide 

 diversity of opinion in regard to the value of the whole opsonic 

 theory, both for diagnostic and for therapeutic purposes, and 

 the stronger authority seems opposed to attributing very great 

 value to the use of opsonins for therapeutic purposes. 



Hektoent finds that the opsonic function of normal and 

 immune serum is due to a distinct body, different from lysins 

 and agglutinins. 



BuxtonJ finds support for Wright's view that the opsonins 

 are a very important factor in immunity. The influence of the 

 opsonins on the bacteria is to make them more acceptable to 



*A. E. Wright and Stewart R. Douglas. An Experimental Investigation of 

 the Role of the Blood Fluids in Connection with Phagocytosis. Proceedings 

 of the Royal Society. Vol. LXXIL, No. 483, p. 357. October 31, 1903. 

 Ibid. Vol. LXXIIL, No. 490, p. 128. February and March, 1904. 



fHektoen. Journ. Infectious Diseases. Vol. Ill, 1906. pp. 434-440. 



%Journ. Med. Research. V. XVI., No. 2, 1907. p. 264. 



