In a previous communication1 I have drawn attention to certain fallacies which attach to Wright's method of estimating the opsonic content of the blood, and have shown that more accurate results can be obtained by estimating the percentage of phagocyting leucocytes. By comparing the figure thus obtained with the figure corresponding to a specimen of pooled normal blood serum, terming the latter value 1, an index is obtained which is directly comparable to Wright's index. For routine work this method will be found more convenient than Wright's method of counting the organisms pro leucocyte and comparing the resulting figure with the corresponding one obtained with normal blood.
If for any reason, however, Wright's method is to be used, I should recommend that the percentage index be calculated at the same time; it will be found a useful check on the former and readily shows up errors that may have been
SIMON CE. THE PERCENTAGE INDEX VERSUS THE BACILLARY INDEX IN THE ESTIMATION OF THE OPSONINS.. JAMA. 1907;XLVIII(2):139-140. doi:10.1001/jama.1907.25220280051002c