BY R. GREIG-SMITH. 557 



polynuclear leucocytes, towards which in the normal or untreated 

 state the}^ are indifferent. In this respect, therefore, the opsonins 

 are identical with the agglutinins. They both prepare the 

 bacteria for inception by the phagocytes. 



The similar behaviour of opsonised and agglutinated bacteria 

 leads one to believe that after all there may be a close analogy 

 between opsonin and agglutinin, and that certain of the points 

 of difference might disappear upon further examination. 



We know that blood serum normally contains small quantities 

 of various agglutinins, but to make the matter certain, especially 

 with regard to the staphylococcus agglutinins, I exnmined normal 

 serum, my own, and found a decided agglutination for Micr. 

 aureus with serum diluted from 3 to 200 times. Suspensions of 

 dead staphylococci which had been killed by heat were also 

 agglutinated. "^ 



The chief difference between the two is found in the action of 

 heat. The opsonins are destroyed at 60°, but there is some 

 diversity of opinion regarding the effect of an exposure at that 

 temperature upon the agglutinins. This is without doubt due to 

 the fact that not only are the agglutinins specific with regard to 

 their affinities for the products of particular bacteria, but they 

 also differ in their behaviour to physical agents such as heat. 

 According to Scheller, normal equine serum contains marked 

 quantities of typhoid agglutinin which is scarcely affected by an 

 exposure to a temperature of 62° for 30 minutes. Human 

 typhoid agglutinin is considerably altered upon heating it at 60° 

 for 15 minutes. In two cases which I tested, the agglutinating 

 powers were reduced to one-seventh and one-tenth respectively. 

 With regard to the normal agglutinins, which occur ordinarily 



• It may be mentioned in this relation that while Wright and Douglas 

 found that heating the staphylococcus suspension to 115° had no influence 

 upon the behaviour of the bacteria towards the opsonins, Bulloch and Atkin 

 demonstrated a reduction of the opsonic action after the bacteria had been 

 heated for longer periods at high temperatures; for example an exposure 

 for 60 minutes at 10U° reduced the phagocytic index (the average number of 

 cells englobed by a polynuclear leucocyte under the conditions of experiment) 

 from 30 to 20. .^-i:— _ 



L S B R A R Y :io| 

 i^ ^^0 ^^ ■ "^^ 





