1. Groups of rats were given a fibre-free diet containing none or one of the three fibre components: pectin, cellulose or galactomannan.2. After feeding for 16 weeks, total protein level and β-glucuronidase (EC 3.2.1.31) activity in the contents and mucosa of jejunum and ileum, and in the contents only of the caecum, were determined.3. The pectin supplement reduced protein concentration in jejunal contents while cellulose reduced protein concentration in the ileal and caecal contents.4. β-Glucuronidase activity of caecal contents was significantly reduced in both the pectin- and cellulose-fed groups.5. Cellulose affected the β-glucuronidase activity of both the ileal contents while pectin reduced the β-glucuronidase of the ileal but not the jejunal contents.6. Dietary fibre components did not significantly affect jejunal or ileal mucosal β-glucuronidase activity.

SYNOPSIS Urinary and serum amino‐acid patterns were studied in 56 premature and full‐term babies by a new technique of combined electrophoresis and chromatography. A changing pattern of urinary amino‐acid excretion with increasing maturity was found, particularly with the basic amino acid lysine and with cystine. We have confirmed previous reports of high excretion of proline and hydroxyproline in infants. High levels of tyrosine in the blood and urine in 4 of the 37 premature babies were possibly due to a combination of high protein intake and late maturation of the enzyme tyrosinase in these infants. The excretion of glutamine was surprisingly low. Possible explanations for this are discussed. Homocitrulline was found in blood and urine of all infants fed with sterilized milk, including breast milk. This is thought to be related to the heating of the milk. Apart from tyrosine and homocitrulline, the pattern of serum amino acids did not differ significantly from that seen in normal adults. Infants malnourished in utero showed amino‐acid patterns which resembled those of babies of similar birthweight rather than similar maturity.