The pigments of sponges

Lysine deficiency in rats of an initial weight of 110-140 g. produces a mild anaemia with a slightly greater reduction in haemoglobin than in red cells.It is suggested that protein deficiency may be a contributory factor in nutritional anaemia.2. There is also a loss of protein from the liver and a hypoproteinaemia, whilst the body protein content seems to be unchanged.The importance of the liver for protein metabolism and its possible role in connexion with the synthesis of serum proteins is discussed.3. None of these symptoms, apart from a loss of body weight, is observed if an adequate diet is restricted in amount to produce weight changes similar to those observed in lysine-deficient animals.It is suggested that the clinical picture is produced by a general interference with protein synthesis and does not represent a specific lesion.The authors wish to thank Glaxo Laboratories Ltd. and Roche Products Ltd. for supplies of vitamins.