202 NORMAL AND PATHOLOGICAL BLOOD 



in lead poisoning, but in certain cases of malarial cachexia it may be 

 equally prominent. The only form of nucleated red cell seen is the 

 normoblast, in very small numbers, or it may not be present. 



Megaloblasts are practically never seen, except in some of the very severe para- 

 sitic anaemias, as the broad Russian tape-worm infection. The red cells generally 

 number between 2,000,000 and 4,000,000, thus differentiating chlorosis. The 

 leukocytes are frequently increased to 15,000. In the anaemia of splenic anaemia 

 there is a marked leukopenia. In anaemias from malignant tumors the color index 

 is usually of the chlorotic type the haemoglobin content of the red cells being 

 more affected than the number. Normoblasts are usually present, and this find- 

 ing may differentiate gastric cancer from ulcer. In bone marrow metastases 

 megaloblasts may be expected. Myelocytes and so-called tumor cells (large cells 

 with faintly-staining vacuolated nuclei and frut little cytoplasm) may also be found. 

 As a rule, there is a moderate leukocytosis in malignant disease. Eosinophiles 

 may be largely increased in sarcoma. 



THE LEUKAEMIAS. 



It is in the leukaemias that we have the greatest increase in the num- 

 ber of white cells. These cases show more or less anaemia, but we may 

 have cases of myelogenous leukaemia showing 250,000 leukocytes per 

 cubic millimeter without particular change in the red cells. The 'more 

 marked the red-cell change the more severe the condition. 



There are two well-defined types of leukaemia, the lymphatic and the 

 splenomyelogenous. It must be borne in mind, however, that while 

 a greater change in the lymphatic glands may produce the lymphatic 

 type, yet even in such cases we expect to find alteration in bone marrow 

 and spleen; that is, there is a general involvement of the haemopoietic 

 system in all leukaemias, the activity being most marked in spleen and 

 bone marrow in certain cases and in lymphatic glands in others. 



Myelogenous leukaemia is a very rare disease, about five times as 

 rare as pernicious anaemia. Lymphoid leukaemia is still more rare. 



Splenomyelogenous Leukaemia (myeloid leukaemia). The differen- 

 tiation of the blood picture of this disease from leukocytosis does not 

 depend on the number of leukocytes, but on the presence and large 

 proportion of myelocytes. We expect both neutrophilic and eosino- 

 philic myelocytes in myeloid leukaemia the proportion of these varies, 

 but, as a rule, the neutrophilic one is the common one. The blood in 

 advanced cases is milky and shows a most marked buffy coat. The 

 marrow is largely replaced by a yellow pyoid material. The spleen 

 may weigh 10 pounds. 



