1912.] 



Method for Opsonic Index Estimations. 



145 



Summary. 



The improvements described have produced : — 



(1) A striking reduction in the liability to error of opsonic estimations 

 when repeatedly tested. 



(2) The results recorded by the new method (Table C) showed a liability 

 to error of about one quarter the magnitude of those recorded in Table A 

 (old method), the experimental conditions being almost comparable. 



(3) The enhanced accuracy is associated with a much reduced range of 

 microbic content of the leucocytes (0 — 14). 



(4) The improved results are attributable to the more even distribution of 

 bacteria amongst the leucocytes (by the removal of the red corpuscles) and 

 by its maintenance during incubation in the opsonic mill. 



(5) No observations were made of any variations in opsonin in health or 

 pathological states. 



I am indebted to Dr. Cavendish Fletcher for his valuable assistance with 

 this work, which unfortunately he had to abandon. 



EEFERENCES. 

 Drs. Glynn and Cox. ' Journal of Pathology,' 1909. 

 Drs. Glynn and Cox. ' Journal of Pathology,' 1912. 



Drs. Greenwood and White. ' Biometrika,' 1909, vol. 6, No. 4 ; 1910, vol. 7, No. 4. 



Dr. Hort. 'British Medical Journal,' February 13, 1909. 



Dr. Ponder. ' Camb. Phil. Soc. Proc.,' 1909, vol. 15, Part I. 



Dr. Rosenow. ' Journal of Infectious Diseases,' 1906. 



Sir A. E. Wright. ' Studies in Immunisation ' (Text-book). 



VOL. LXXXV. — B. 



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