#1. The observations on which this thesis is based were made by me in the course of routine duties as an assistant in general practice. #2. A description of the type of practice is given and of the method of selection of cases for examination. #3. The desirability of performing blood counts as a routine diagnostic measure in general practice is urged. #4. The normal figures for haemoglobin and red blood corpuscles are stated. #5. The various methods by which the percentage of circulating haemoglöbin in healthy blood is calculated, are described in some detail. #6. The Haldane scale is defined. #7. The necessity for standardisation of all haemoglobinometers in terms of absolute values is stressed. #8. The reasons for rejecting the uncorrected figures given by my Sahli Haemoglobinometer are stated. #9. The standardisation of my Haemoglobinometer is described. #10. The phenomenon of the increasing depth of colour in a newly prepared sßlution of acid haematin is described. #11. Figures obtained from an investigation of this phenomenon are used to establish a method for the quick conversion of readings on the Sahli Haemoglobinometer into percentages on the Haldane scale. #12. The principle of the diffraction method of measur :ing the mean red cell diameter is described and its limitations outlined. #13. My experience with an instrument of this type are given. #14. The case notes of 86 patients observed over a period of 1* years in general practice, are given together with the blood picture, treatment, and progress notes. #15. Three cases of pernicious anaemia observed in hospital are added. #16. The clinical classification of 68 cases of anaemi in general practice is given. The cases fall int the following groups, according to age: 1. Children 14 cases; 2. Adolescents 1 case; 3. Adult males 7 cases; 4. Adult females 46 cases. The cliñical subdivision of these groups reveal the following:- Hypochromic anaemia in children 14 cases; Hypochromic anaemia in adolescents., 1 case; Pernicious anaemia 4 case;: Hypochromic anaemia in adult males 5 case;; Hypochromic anaemia in females 44 cases; Total....68 cases. #17. When cases of pernicious anaemia and cases with a demonstrable organic basis are excluded, only 33 cases of idiopathic hypochromic anaemia remain. Of these 30 occurred in adult females, and 3 in children. #18. It is therefore concluded that an idiopathic hypochromic anaemia in which no underlying pathology is found is common only in children and females. #19. 26 of the cases of idiopathic anaemia in adult females are discussed as a whole. #20. The importance of dietary deficiency and iron los due to menstruation are stressed. #21. The high incidence of the condition in the re- productive period, and especially towards the menopause is stressed. #22. The role of repeated pregnancies in the aetiology of hypochromic anaemia is minimised. #23. The symptomatology is discussed and the incidence of glossitis, dysphagia, koilonychia, dyspepsia, amenorrhoea, and menorrhagia are noted: 1. In relation to the total number of cases (26); 2. In relation to the degree of anaemia present. #24. The response to treatment is indicated. #25. The other hypochromic anaemias found in adult females are very briefly noted under appropriate headings. #26. Seven cases of pernicious anaemia are discussed. #27. Two cases of hyperpoiesis associated with pernicious anaemia are described. #28. The financial aspect of pernicious anaemia is stressed, and the average weekly cost of maintenance of the seven cases are noted in detail. #29. It is shown that parenteral injection is a cheaper method of therapy than the exhibition of raw liver orally. #30. It is suggested that Anahaemin is a cheaper and more efficient liver extract than Campolon. #31. cases of hypochromic anaemia occurring in adult males are briefly noted under appropriate headings. #32. Fourteen cases of hypochromic anaemia in children are discussed as a whole. The associated pathological lesions are noted. #33. The importance of thorough examination of anaemic children in order to discover the underlying pathology, is illustrated.