Clinical examination of the blood and its technique : a manual for students and practitioners / by A. Pappenheim ; translated and adapted from the German by R. Donaldson.

  • Pappenheim, A (Artur), 1870-
Date:
1914
Catalogue details

Licence: In copyright

Credit: Clinical examination of the blood and its technique : a manual for students and practitioners / by A. Pappenheim ; translated and adapted from the German by R. Donaldson. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    tively by a preliminary calculation and then of multiplying the number thus obtained in the manner shown above : it is simpler and more convement to reduce aU these calculations to one step, so sim- phfying the formula. Since a considerable number of large squares, each equal to i6 small ones, should be counted, it is obviously advisable to count through a number of large squares, divisible by 4. Four large squares may be taken as the minimum number to be of any service. If one is simply in the habit of never counting more than 4 large squares, then X is always equal to 4- The above formula will then be reduced to the following terms:— N X M X 1000 16 In enumerating the red cells when the dilution is I in 200, if 100 small squares are counted (i.e., 6 large and 4 small squares), we need only multiply the number counted (N) by 8000. Thus the number of red cells per c.mm. = N X 8000. It might be added that, in determining the number of red blood cor- puscles, a dilution of i in 200 should be used ; for the whites a dilution of i in 10. In estimating the number of red cells in the rare cases of polycythasmia, still higher dilutions, however, must be used. Thus, if we suck up the blood to the mark -4 we get a dilution of i in 250, if only to -2 the dilution is I in 500. For the enumeration or red blood corpuscles in 4