. Essentials of laboratory diagnosis; designed for students and practitioners. he total number ofsquares (400) (Fig. 16), and to multiply the total number of 3 Sahlis Diagnosis, quoting Capps : loc. tit. ENUMERATION OF THE CORPUSCLES. 63 calls counted by two hundred ; the result will be the total numberof white cells per cubic millimeter of blood. Enumeration of the Leukocytes.—Explanatory note: yi000cubic millimeter equals the cubic capacity of one small square. y2oequals the dilution of the blood, and 400 (all) the small squares the number of leukocytes per millimeter of undilut
. Essentials of laboratory diagnosis; designed for students and practitioners. he total number ofsquares (400) (Fig. 16), and to multiply the total number of 3 Sahlis Diagnosis, quoting Capps : loc. tit. ENUMERATION OF THE CORPUSCLES. 63 calls counted by two hundred ; the result will be the total numberof white cells per cubic millimeter of blood. Enumeration of the Leukocytes.—Explanatory note: yi000cubic millimeter equals the cubic capacity of one small square. y2oequals the dilution of the blood, and 400 (all) the small squares the number of leukocytes per millimeter of undiluted blood will befound by dividing the number of cells counted by the number of squarescounted and multiplying by the dilution times 4000, viz.:—Let x equalthe number of leukocytes per cubic millimeter, and y equal the numberof cells counted in 400 small squares. Then, ^ X 20 X 4000 = x or,v X 200 — x = leukocytes per cubic millimeter of undiluted blood. Improved Methods of Counting.—It is an advantage whencounting the leukocytes to use a Zappert ruled disc. This has. Fig. 16.—Ruling of Chamber of Thoma-Zeiss Hemocytometer. upon it the same ruling of 400 small squares in the centralsquare millimeter. as in the Thoma-Zeiss, but around it, inaddition, are ruled eight other squares of the same size, whichif required may each be divided into four. Each large squarerepresents %0 cubic millimeter when the counting chamber iscovered. AY hen using Zapperts chamber, first the leukocytes in thecentral square millimeter, and then the other eight squares, are 64 THE BLOOD. counted with a low power, the normal being about 35 per a dilution of 1: 20. The formula would be:— Number of leuko- Cubic contents cytes counted Dilution of square 321 X 20 X 10^ ( Number of leukocyte? Number of squares counted. 9 I per (7133). This modification has been improved by Ewing and byTiirck (Fig. IT) in such a way that the four large corner squares,each of 1 square millimeter, are
Size: 1594px × 1568px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcetc, bookyear191
