Effect of undernutrition in early life on physical and mental development.

It was pointed out by Trowell, Davis, and Dean (1954) that, 'Nothing is known about the completeness of recovery from severe kwashiorkor', and this is to a large extent still true. An increase in the body weight is admittedly a sign of recovery, and indeed a very important criterion of it, but unless the final weight and height attained are also known it is impossible to say whether it has been complete. The experiments on animals give some information about this problem. McCance and Widdowson (1962) showed that the body weights of rats undernourished during suckling never reached those of their controls in spite of subsequent unlimited food. Undernutrition for the first six months of life can also affect the final stature of cockerels (Pratt and McCance, 1961), but this has not been found to be true of all species and for these differences references should be made to Aron (1911), Moulton, Trowbridge, and Haigh (1921), Jackson (1925), Clarke and Smith (1938), Crichton, Aitken, and Boyne (1959), and McCance (1962). The extent of the undernutrition and the age at which it affects the animal are also certainly important (Widdowson and McCance, 1963). Even less is known about the mental than about the physical development of children after a period of undernutrition (Stoch and Smythe, 1963; Graham, 1964). Attention has been drawn to defects in their ability to learn a language (Waterlow, Cravioto, and Stephen, 1960), which is one of the most important ways of estimating the intelligence of a child (Stevanovic, 1937). Jersild (1955) has stated that, 'A positive relationship is usually found between language ability and mental ability.' Many authors, moreover (Porter, 1895a, b; Boas, 1940; Tanner, 1955), have found that children who are physically advanced for their age score higher in mental tests than those who are less mature, but of the same chronological age. Lat, Widdowson, and McCance (1960) showed this to be true also of rats. Material and Methods