APPENDIX II 1 



SOME COMPARATIVE MEASUREMENTS OF THE LIVES OF LEUCO- 

 CYTES 2 WHEN THE CELLS ARE RESTING IN THE PLASMATA 

 OF DIFFERENT PERSONS 



AND THE POSSIBLE APPLICATION OF SUCH MEASUREMENTS AS AN AID TO 

 DIAGNOSIS IN INFECTIVE DISEASE 



OF recent years I have been endeavouring to ascertain the effect 

 produced by one person's plasma on the life of another person's 

 leucocytes. It appeared reasonable to suppose that the plasma of 

 a person suffering from an infective disease would be poisonous to 

 the leucocytes of healthy persons. If this is the case it might also 

 be reasonable to suppose that the same plasma would not be so 

 poisonous to the leucocytes of another person suffering from the 

 same disease, because it is probable that the cells would be already 

 used to, or immune against, the toxin ; and furthermore that if the 

 toxin of one infective disease differs from the toxin of another 

 infective disease, it might be inferred that an immunity on the 

 part of a leucocyte against one disease will not render it immune 

 against another. Therefore, provided it is possible to tell accurately 

 when a leucocyte is dead that is, if one can differentiate a living 



1 A method for estimating the number of living and dead leucocytes con- 

 tained in a given sample of blood; and another convenient formula for the 

 preparation of "kinetic jelly." Being a paper reprinted from The Lancet of 

 February 6, 1909, by kind permission of the and Editor of that Journal. 



2 The word "leucocyte" refers to the neutrophile polymorphonuclear 

 leucocyte. 



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