228 NORMAL AND PATHOLOGICAL BLOOD 



The trilobed nucleus stains less intensely than the granules. As a rule, 

 the mast cell is about the size of a polymorphonuclear. 

 In a differential count of normal blood we find about the following percentages. 



Polymorphonuclears, 65 to 70%, about 5000 per cu. mm. 

 Small lymphocytes, 20 to 30% about 1500 per cu. mm. 

 Large lymphocytes, 2 to 6%, about 200 per cu. mm. 

 Large mononuclears, i to 2%, about 100 per cu. mm. 

 Transitionals, 2 to 4%, about 200 per cu. mm. 



Eosinophiles, i to 2%, about 100 per cu. mm. 



Mast cells, M to >%, about 25 per cu. mm. 



NOTE: The lymphocyte percentage of infants is about 60. 



DIFFERENTIAL COUNT 

 

 In making a differential count I would recommend the following 



from the directions of Schilling-Torgau. 



It will be remembered that considerable interest was raised a few years ago in what 

 was termed the Arneth index. In this the more normal, more mature, better resist- 

 ing polymorphonuclears were considered to have three or four lobes to the nuclear 

 structure, even occasionally five. The immature cells had only one or at most two 

 lobes to the nucleus. The index was obtained by adding the percentages of cells 

 showing one and two lobes to one-half the percentage of those with three lobes. As 

 will be understood a high percentage of these immature cells was unfavorable in prog- 

 nosis. These cells are graded from left to right I, II, III, IV, V, as to separate 

 masses in the nucleus, so that when the percentage is shoved or displaced to the left 

 it indicates an increase in the immature cells. 



Schilling-Torgau divides his polymorphonuclears into i. the myelocyte which is 

 always of course a pathological cell; 2. the immature form polymorphonuclear. In 

 this there is a close resemblance to the neutrophile myelocyte but there is a nuclear 

 indentation instead of the round nucleus of the myelocyte. It is this cell which often 

 puzzles us as to whether to regard it as a true myelocyte. It is the metamyelocyte 

 of many authorities. 3. Between the mature or segmented polymorphonuclear 

 and the immature one or metamyelocyte we have what may be designated the band 

 form nucleated one. These show the type of nucleus which one is familiar with in 

 the nucleus of the transitional. 4. The mature, multilobed or segmented nucleus of 

 the typical polymorphonuclear. 



It would seem that if all laboratory workers would agree upon some 

 single method of recording differential counts it would be advantageous. 



In the differential count he not only divides up the polymorphonuclears but 

 makes no separation of small from large lymphocytes. Although I have always 

 divided lymphocytes into large and small ones I believe it unnecessary and imprac- 

 tical and shall henceforth group all such cells in one grouping. The statement that 

 large mononuclears and transitionals are cells of a similar origin, type and significance 

 has always been my idea. 



