BY R. GREIG-SMITH. 567 



higher base level of opsonic action which, according to Wright, 

 follow the inoculation of staphylococcus vaccine. Another 

 similarity between opsonins and agglutinins is observed in the 

 power which bacteria have of fixing and removing them both 

 from solutions. 



The points of possible difference between the opsonins and 

 agglutinins relate to the experiments of others upon the simul- 

 taneous rise and fall of the two during immunisation. A very 

 strong indictment against their identity is made by Wright and 

 Douglas,* who say that " Normal human serum does not exert 

 any characteristic agglutinating action upon the staphylococcus. 

 Such agglutination as is obtained is not very sensibly increased 

 under the influence of staphylococcus inoculations."! 



The races of bacteria are known to vary in their agglutinability, 

 and the staphylococcus is no exception. Otto| found that the 

 agglutinability of races of the truly pathogenic staphylococci 

 varied. Nicoles and Lesieur§ immunised a goat to a race of 



* Proc. Roy. Soc. Ixxiv., 1904, 148. 

 t At another place they say that no parallel exists between the opsonic 

 and agglutinating powers of the blood of tubercular patients. The agglu- 

 tination of Bac. tuberculosis is difficult to determine. The bacterium grows 

 very slowly, and in the cultures there are many old cells. It is a peculiarity 

 of some bacteria that in their senescence they produce autoagglutinins and 

 perhaps autolysins. Such has been demonstrated by Emmerich and Loew 

 in the case of Bac. pyocyaneus. Bac. tuberculosis produces autoagglutinins, 

 and it is difficult to distribute cultures uniformly in saline solutions. Wright 

 and Douglas ground up their cultures in an agate mortar with a O'l % 

 solution of common salt and obtained a suspension of bacterial fragments 

 in which the autoagglutinatire action was in abeyance. Although this 

 strength of salt is not the most favourable, it is still sufficient to enable 

 agglutination to become manifest in an hour at 37*=". But it is probable 

 that any agglutination that did appear might have been a combination of 

 true agglutination and autoagglutination, the latter being induced by the 

 salts added with the serum. For this reason Bac. tuberculosis does not 

 promise to be suitable for showing analogies between agglutination and 



opsonisation. 



+ Cent. f. Bact. (Orig.) xxxiv. 44. 



§ Ibid. (Ref.) xxxi. 158. 



