556 IDENTITY OF OPSONINS WITH NORMAL AGGLUTININS, 



included staphylococci, pneumococci and the micro-organisms of 

 plague, Malta fever, dysentery, diphtheria, xerosis, anthrax and 

 cholera. Bac. tuberculosis'*' is also capable of being opsonised. 



The opsonins are thermolabile, being destroyed by an exposure 

 to a temperature of 60° for 15 minutes. This was confirmed by 

 Bulloch and Atkin,t who also showed that a longer exposure at 

 a lower temperature had the same destructive ejBfect. In their 

 conclusions they write, " The action of heat is to destroy the 

 opsonin, and not merely to convert it into a non-opsonisable 

 modification." 



Wright and Douglas, and also Bulloch and Atkin, worked upon 

 the staphylococcus, and when the temperature of destruction of 

 the opsonins is given at 60° it can only refer to staphjdococcus 

 opsonin. In their second paper, published before that of Bulloch 

 and Atkin, Wright and Douglas show that the opsonins are not 

 entirely destroyed by heat when bacteria other than the staphy- 

 lococcus are examined. In fact, staphylococcus opsonin appears 

 to be peculiar in being completely destroyed at so low a temper- 

 ature as 60'' in 15 minutes. Still this is given by these authors 

 as the destructive temperature for the opsonins, and we must use 

 it as a working basis. 



The action of the opsonins is to prepare the bacteria for 

 inception by the phagocytes. This might be accomplished in 

 three ways. First, the capsule may be altered to a chemotactic 

 modification; secondly, it may be dissolved; and thirdly, it may 

 be covered by a film of a positively chemotactic precipitate. 



As the bacteria appear quite normal after opsonisation, the 

 capsule is probably not dissolved. It may be altered, or it may 

 be covered. Neither alteration nor covering is visible, but the 

 same can be said about the films upon bacteria that have been 

 agglutinated. 



I have already shown | that bacteria such as Bac. typhis which 

 have been agglutinated, are capable of being englobed by the 



* Proc. Roy. Soc. Ixxiv. (499), 159; and Urwick, Brit. Med. Journ., July 

 22nd, 1905, p. 172. 



t Proc. Roy. Soc. Ixxiv. (504), 1905, 379. 

 + ^?i;eap.2S9. 



