﻿X. OPSONIC ACTION OP PLAGUE SEBUM. 



As is now generally known, Wright and Douglas so in 1903 proposed 

 the term "opsonins" to designate the elements in the blood which modi- 

 fied the bacteria in a manner which rendered them a ready prey to the 

 jjhagocytes. Their important article, at the time of its appearance, did 

 not excite the attention which it merited, but in 1904 and 1905 they, 

 together with Bullock, 81 undertook further studies relating to the varia- 

 tions of the opsonic content of the blood in certain infections and explained 

 the practical results to be obtained from tbe observation of the opsonic 

 index. These publications attracted wide attention. During the past 

 year many articles have appeared relating to the presence of opsonins 

 in different infections and of the practical results to be obtained by 

 increasing the opsonic index through the injection of bacterial vaccines. 

 While some of this work has been done by trained investigators, much 

 of it has been performed by men who may be considered new to the 

 field and it is questionable whether all of the claims of the practical 

 results obtained with the various infections will be justified by more 

 careful work in the future. There are many sources of error in determin- 

 ing the opsonic index, and the personal equation is of considerable im- 

 portance when the method described by Wright is employed. 



Among the more important articles on this subject which have appeared 

 during the past year, besides those of Wright, may be particularly men- 

 tioned those of Hektoen 82 and his pupils and of Simon, Bosenow and 

 Porter 83 in the United States, and of Muir and Martin in Great Britain. 



A discussion of the entire subject can not here be entered into. 

 Hektoen and Bullock believed that the opsonins might be regarded as 

 distinct from the other anti-bodies. However, it does not seem to me 

 that this has been at all conclusively established, and in my experimental 

 work on the subject I have not been able to convince myself that in the 

 "opsonic" action in plague we have to do with any other factors than the 

 binding of the receptors of the bacteria by amboceptors of the serum 

 and of the union of the complement in the usual way, as in bacteriolysis, 

 and believe that it is in this manner that the bacteria are prepared for 

 phagocytosis. However, obviously the complement does not always neces- 

 sarily cause lysis, although it always enters into the reaction. 



m Proc. Roy. Soc. Lond. (1903), 72, 357. 



61 Ibid. (1904), 73, 128, and Lancet (1905), 2, 1598 and 1603. These articles 

 contain the other important references to Wright's work. 



62 J. Am. Med. Ass. (1906), 46, 1407, and J. Infect. Dis. (1906), 3, 434. 

 S3 J. Am. Med, Ass. (1906), 47, 1722. 



264 



