BY R. GREIG-SMITH. 565 



In the table, "0" means no agglutination visible, "1" represents 

 small suspended floccules, "2" stands for a partial flocculent 

 sedimentation, and " 3 " indicates a complete flocculent sedi- 

 mentation with a faint opalescence. The small sedimentation 

 tubes were kept at 37*^, excepting in the case of the heated 

 serum, which stood overnight at room temperature (20°). 



We see that potassium chloride agglutinated suspensions of 

 living staphylococci more readily than sodium chloride, and that 

 heating the serum to 60° for 15 minutes prohibited the rapid 

 action of the staphylococcus agglutinin. That the action of the 

 heat was not to destroy the agglutinin was shown by the com- 

 plete sedimentation of the tests at the end of 20 hours. The 

 microscopical examination of the sediments after that time proved 

 that the partial sedimentation of the check test was due to 

 gravitation, for the bacteria were singly and in pairs. In all the 

 tests which had been treated with heated serum small clumps 

 were found in addition to the individual and paired cells. The 

 influence of the dilution, in increasing the agglutination, as seen 

 in the tests with 5-, 10- and 15-fold dilutions, is noteworthy in 

 view of the fact that a relatively greater opsonic eff'ect is obtained 

 upon diluting serum (p. 563). 



The staphylococci lend themselves admirably to experiments 

 such as these. They are comparatively large, they stain very 

 deeply, and they are not easily bacteriolysed. Enumeration is 

 easy, and the results can be relied upon. With other bacteria 

 there is more or less swelling and disintegration within the leuco- 

 cytes. Wright and Douglas noted this in their work upon the 

 other bacteria. 



Some of the bacteria that had been examined by these investi- 

 gators were employed in an experiment which had for its object 

 the recovery of the opsonic power after its retardation by heat. 

 The serum was diluted with normal saline to make a 10 % solu- 

 tion. The films showed that a considerable bacteriolysis had 

 occurred within the polynuclear white blood corpuscles. All 

 stages between the normal bacterium and the smallest granule, 

 the final visible result of bacteriolytic action, were seen. It was 

 37 



