238 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



and the diagnosis is unlikely with the lymphocytes much below 

 40 per cent. If you have not yet seen a megaloblast, continue to 

 search for them, as they are usually present in pernicious anaemia 

 of moderate severity, and comparatively rare in other conditions, 

 except in children. The significance of the discovery of a single 

 megaloblast will depend on the other findings ; if these point to 

 pernicious anaemia, the megaloblast may be taken as clinching 

 the diagnosis, but if they are not of this nature its importance is 

 much less. Do not exclude pernicious aneemia because no 

 megaloblasts are found. According to Ehrlich and others, they 

 always exceed the normoblasts in numbers, but this is not a safe 

 guide, as in some cases you may find normoblasts alone on some 

 occasions, and megaloblasts and normoblasts in differing pro- 

 portions on others. Polychromasia and granular degeneration and 

 poikilocytosis are common in advanced stages of the disease, but 

 the diagnosis ought to have been made before their appearaince. 



The diagnosis from secondary ancemia rests on the high colour- 

 index, the leucopenia, lymphocytosis, nucleated corpuscles and 

 megalocytes, and is usually easy. Anaemia associated with 

 intestinal parasites may resemble idiopathic pernicious anaemia in 

 every respect except in that the former is accompanied by 

 eosinophilia. In pernicious anaemia the eosinophiles are usually 

 low, and if they exceed 4 per cent, the faeces should be searched 

 for the ova of parasites (especially ankylostoma, bothriocephalus 

 and oxyuris). The anaemia of carcinoma of the stomach and other 

 gastric diseases may closely resemble pernicious anasmia, but in 

 most cases there is a high leucocyte count, with increase of 

 polynuclears and diminution of lymphocytes. 



Chlorosis. — Here there is a moderate reduction of the red 

 corpuscles and a great reduction of the haemoglobin ; the colour- 

 index falls, therefore, and 0-5 may be taken as an average, 

 though much lower figures occur. The corpuscles are pale, but 

 abnormal forms are rare. Normoblasts are very rare, but when 

 they occur usually herald a rapid improvement. The leucocytes 

 are normal in numbers, or there may be leucopenia. 



It may be confounded with various forms of secondary anasmia, 

 but in them the colour-index is usually higher, and the leucocytes, 

 especially the polynuclears, tend to be increased. 



Myelogenous LeucocythvEmia (" spleno-medullary "). — There 

 is an enormous increase in leucocytes, which in an average case 

 may amount to 400,000. A II varieties of leucocytes are increased 



