Practical physiological chemistry; a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . ution the leucocytes may be counted in the same specimen of blood in whichthe erythrocytes are counted. When this is done it is customary to use a sUdeprovided with Zapperts modified niling (Fig. gSj. This method is rather moreaccurate than the older one of counting the leucocytes in a separate specimenof blood. Furthermore, it is obviously preferable to count both the eryth-rocytes and the leucocytes from the same blood sample. To insure accuracyth
Practical physiological chemistry; a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . ution the leucocytes may be counted in the same specimen of blood in whichthe erythrocytes are counted. When this is done it is customary to use a sUdeprovided with Zapperts modified niling (Fig. gSj. This method is rather moreaccurate than the older one of counting the leucocytes in a separate specimenof blood. Furthermore, it is obviously preferable to count both the eryth-rocytes and the leucocytes from the same blood sample. To insure accuracythe nvunber of leucocytes within the whole ruled region should be determined indupUcate blood samples. This includes the examination of an area eighteentimes as great as the old style Thoma-Zeiss central ruUng. This region thenwould correspond to 3600 of the small squares and, if duphcate examinations were» made, the total bumber of small squares examined would aggregate 7200. The calculation would be as follows: Number of leucocvtes in 7200 ,, ,, . Number of leucocytes per cubic X 200X4000 —7200= •„• . squares ^ ^-^t 1 millimeter. 1. Fig. 98.—Zapperts Modified Ruling OF Thoma-Zeiss Counting Chamber. iDa Cosla.) If a Zappert slide is not available, a good plan to follow is to place adiaphragm in the tube of the ocular of the microscope consisting of acircle of black cardboard or metaP having a square hole in the center ofsuch a size as to allow of the examination of exactly 100 squares or one-fourth of a square millimeter at one time. With this arrangement anyportion of the specimen may be examined and counted whether withinor without the ruled area. In counting by means of this dcNice it is, ofcourse, helpful if the microscope is provided with a mechanical stage,but even without this arrangement, if the observer is careful to see thatthe leucocytes at the extreme boundary of one field move to the oppositeboundary when the position of the slide is changed, the device m
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbiochem, bookyear1916
