88 SPECIAL DISEASES OF THE BLOOD 



Liter the lib index is nearly normal though there is considerable 

 difficulty in obtaining the amount of hemoglobin owing to the 

 changed color produced by the excess of leucocytes. Changes in 

 the size, shape and staining of the red corpuscles are found corre- 

 sponding to the degree of anemia present. As a rule many ery- 

 throblasts are found, even in cases showing no external signs of 

 anemia. In nine cases DaCosta found from 748 to 12,913 ery- 

 throblasts per cmm. with an average of 5,931 per cmm. Of these 

 the majority were normoblasts. Megaloblasts occur, but in 

 smaller numbers. Erythroblasts with mitotic nuclei are found 

 occasionally. 



The most characteristic changes are found in the leucocytes. 

 Their number is generally excessively increased. The average 

 number in Cabot's cases was 385,000 per cmm., maximum 

 1,072,000, minimum 98,000 per cmm. In acute cases the number 

 may not be greater than in cases of inflammatory leucocytosis. 

 The appearance of a stained preparation is characteristic. Of the 

 leucocytes a large number are myelocytes, mostly metamyelocytes 

 and the variety with fine acidophile granules with a comparatively 

 small number of eosinophilic myelocytes in chronic cases. All 

 stages between myelocytes and polymorphonuclears are en- 

 countered. Polymorphonuclears occur in large numbers but with 

 smaller percentages than in normal blood. Lymphocytes are 

 present in small percentages. Eosinophils occur in large numbers 

 but in about the normal proportion. Mast cells are usually found 

 in rather large numbers. In different cases considerable variations 

 are found especially in the mast cells and eosinophiles. Cabot 

 obtained the following average percentages in 41 cases: myelocytes, 

 32.5%, polymorphs, 47.5%, small lymphocytes, 5.2%, large 

 lymphocytes, 5.4%, eosinophiles, 4.4%, and mast cells, 5%. De- 

 generative changes in the leucocytes are commonly seen. The 

 nuclei of some cells may appear pale and swollen; hydropic nuclei 

 sometimes are found. In others the nuclei may be fragmented, the 

 parts staining deeply. The granules of the polymorphs and 

 myelocytes may be few or absent. Variations in the size and 

 staining of the fine acidophile granules are often seen. 



With intercurrent infection the character of the blood may 1"' 

 greatly altered. The number of leucocytes has been observed to 

 fall from excessively hi<rh numbers to normal or even below the 



