It haslong been known that certain cases of carcinoma of the stomach are attended from an early period by an extreme degree of anaemia, the symptoms of which take precedence of those arising from the gastric lesion and occasion considerable difficulties in diagnosis. A careful consideration of the various cases of this description which have come under our notice has convinced us that at least three varieties of anaemia may accompany the onset of the malignant disease, each of which is attended by definite alterations of the blood. The first and most usual type is that in which the anaemia is the result of internal haemorrhage, which, owing to the absence of vomiting, has remained unrecognised. In the second class are included those cases where the blood so closely resembles that of pernicious anaemia that from a clinical standpoint the two complaints may be said to coexist. The third group comprises those rare instances in which enlargement of the spleen and the presence of an excess of leucocytes in the blood simulate leucocythaemia.