1. Sixteen male cross-bred lambs were given four diets, which differed in the ratio of protein to energy. The protein contents of the diets (on a dry-matter basis) were: 6.1% (diet A), 11.9% (diet B), 17.5% (diet C) and 22.9% (diet D).

2. The experimental period of 7 weeks was divided into two 2-week periods (periods 1 and 2), and one 3-week period. The diets given to the lambs were changed between period 1 and period 2. In period 3 all the lambs were given the same dietary treatment as in period 2.

3. The daily feed intake of the lambs was regulated according to live weight. Adjustments were made at the beginning of period 1 and of period 2. The level of feeding was 121 kcal/kg live weight 24 h. In period 3 the intake was the same as in period 2.

4. Diet digestibility, live-weight gain, and nitrogen and sulphur balances were calculated for each lamb on each diet in all the periods. Wool growth on sample areas was measured over a 2-week and a 4-week period. These wool growth periods corresponded to treatment period 1, and treatment periods 2 and 3, respectively. At the end of the experiment the lambs were slaughtered and the composition of carcass and organs was determined.

5. The mean digestibilities of energy, N, ether extractives and dry matter increased significantly as the protein content of the diet increased.

6. The live-weight gain increased with increasing protein content of the diets, but only the difference between the means for diet A and all other diets was significant.

7. The N and S balances increased with increasing intake of apparently digested N and S, and all differences between the means for individual diets were highly significant.

8. There was a significant correlation between N balance and live-weight gain for each diet. However, when compared at the same late of gain, N balance increased as the protein content or the diet increased.

9. Wool growth on the sample areas increased with an increase in the protein content of the diet and all differences between the means for individual diets were highly significant. There were no significant differences between the dietary treatments in their effect on the N and S contents of the wool. The mean values were 15.7% N and 2.87% S.

10. The retention of N in the wool grown did not account for the increased N retention on the diets of higher protein content. The lambs given diet A, retained more N and S in wool than was supplied by the diet.

11. The percentage of fat in the carcass decreased, and the percentage of protein increased as the protein content of the diet increased. The percentages of moisture and ash were not significantly affected by the dietary treatments.

12. The percentages of moisture in the liver, pancreas and muscle decreased and the percentages of protein in the liver and muscle increased as the protein content of the diet increased. The ratio of N in the organs (with the exception of the spleen and pancreas) to N in the carcass was highest for lambs given the diet with least protein (diet A).

1. The nutrient contents of diets consumed by families in the lower income groups in Lagos are compared with published values for diets consumed by Nigerians in rural areas.

2. Qualitatively, the dietary patterns of urban dwellers tended to resemble those of the regions from which they had migrated; attention is drawn to certain exceptions.

3. Quantitatively, urban diets resembled those in rural areas in (a) providing a lower proportion, in relation to requirements, of calories rather than of protein; and (b) allowing children lower intakes of all nutrients, in relation to requirements, than adults.

4. Restriction of calorie intake resulted in diversion of dietary protein to energy production, and this in turn led to low mean body-weights of children and of adults.

1. The ‘landing’ and ‘swimming’ tests have been used to detect the onset of the neurological manifestations of toxicity of β,β-iminodipropionitrile (IDPN) in rats.

2. Rats on diets of net percentage of dietary protein calories (NDpCal%) of 10.1, 6.2 or 4.6 developed the syndrome later than those on diets of lower protein value.

3. L-Thyroxine did not prevent the development of the ECC-syndrome, but only delayed the onset of the action of IDPN.

1. Thirty-three cross-bred lambs were given reconstituted dried whole cow's milk from 1 week of age at different levels of intake and at different frequencies of feeding.

2. Feeding frequency had no effect on live-weight gain, N retention or total body composition.

3. Lambs given two feeds daily had significantly heavier abomasums than pair-fed lambs given six feeds daily.

4. The weights of fat, protein (N x 6.25) and water in the body were closely related to empty body weight; body composition (% of empty body) was not significantly affected by the level of milk intake or by the rate of growth.

5. Live-weight gain was closely related to energy intake (r = +0.99) and to N retention (r = +0.97). A live-weight gain of 100 g was associated with an intake of 511 kcal and a N retention of 2.28 g N.

1. Five male cross-bred lambs at the age of 3 weeks were starved for a period of 4 days. The utilization of nitrogen, energy and minerals was compared with the pre-starvation and post-starvation periods, when the lambs were given reconstituted dried whole cow's milk.

2. The mean loss in weight during starvation was 253 g/24 h. The gain in weight during realimentation was significantly greater than that in the pre-starvation period, when adjusted for differences in energy intake.

3. The urinary loss of N during starvation was 478 mg N/kg live weight 24 h. During realimentation the urinary N loss was greater than during the pie-starvation period. A higher urea excretion during realimentation was responsible for the increased urinary N.

4. Excretion of ammonia, creatine, amino acid and purine base N increased during starvation. Excretion of creatinine N remained constant.

5. The increase in total sulphur excretion during starvation was due mainly to an increase in the inorganic sulphate fraction. The ratio of N to S of 27: 1 during starvation was much greater than would be expected from the katabolism of muscle tissue alone (ratio N to S = 16.2:1).

6. The titratable acidity and acetone excretion in the urine increased during starvation.

7. There was a marked reduction in the urinary excretion of chloride, potassium and sodium during starvation, an increase in the excretion of phosphorus, but little change in the excretion of calcium and magnesium. The loss of minerals was not closely related to the losses predicted from muscle tissue alone.

8. Pulse rate, respiratory rate, and rectal temperature all decreased during starvation. Heat production decreased after 1 day of starvation, but was relatively constant thereafter.

9. Blood urea concentrations did not change significantly during starvation.

10. The results for the lamb were in reasonable agreement with published results for the calf, except for the marked ketone acidosis and considerable increase in the excretion of purine N. The losses during starvation differed from those with the adult sheep in showing a relatively greater loss of body protein.

1. Urinary excretion of total ether-soluble acids and of methylmalonic acid was studied in rats on vitamin B12-deficient diets with and without a vitamin B12 supplement.

2. It was shown that urinary excretion of total ether-soluble acids and methylmalonic acid was increased in vitamin B12-deficient rats and that this increase was somewhat variable between individual animals, males and females, and rats from different litters.

3. The increased excretion of these acids could readily be reversed by supplementing the diet with vitamin B12.

1. The oxidative stability of lipids in the tissues (erythrocytes, liver and depot fat) from vitamin E-deficient rats was not improved by feeding these animals, for a period of 39–55 days before killing, on a vitamin E-free diet richly supplemented with the flavonoid antioxidants quercetin (3,5,7,3',4'-pentahydroxyflavone) and flavone (3,7,8,2',5'-pentahydroxy-6-tert.-butyl flavone).

2. Addition of α-tocopherol (in the form of α-tocophery1 acetate) to the diet relieved, as expected, the investigated symptoms of vitamin E deficiency and greatly improved the stability of the tissue lipids.

3. Quercetin and flavone, when added in vitro to liver homogenate or to extracted adipose tissue, strongly retarded oxidation. It was concluded that those flavonols either were not absorbed by the animals or were destroyed in the body.

1. The methods for estimating lignin based on 72% sulphuric acid are lengthy and usually require large corrections for the residual nitrogenous impurities. The steps used in the initial purification of lignin, and particularly those concerned with the removal of nitrogenous impurities using proteolytic enzymes, have been investigated.

2. The conditions that remove the maximum amount of nitrogen were investigated. The nitrogenous material remaining in the lignin isolated by the adopted procedure was partly characterized, and it was shown that about half of the resistant N could be obtained in the form of amino acids which were presumably present in the lignin in the form of protein. The amino acid compositions of the resistant nitrogenous material in lignin derived from grass, and in lignin derived from faeces of sheep, when the same grass was given, were compared. They were found to be sufficiently similar to suggest a common origin.

3. A modified procedure is proposed and described in detail; it is suitable for routine work.

4. Comparisons were made between the results obtained by determining lignin in forage and faeces samples by the method now presented and those obtained by the method used previously.

1. Iron deficiency was induced in albino rats by a milk-powder diet. Control groups were given milk powder plus an iron source.

2. The haemoglobin content of the blood was determined once each month. When the haemoglobin level fell to 10 g/100 ml or less in the deficient animals, determinations were made of the vitamin C content of 24 h urine as well as of liver, kidney, adrenals, brain and blood. Additional studies were made of in vitro synthesis of the vitamin by liver homogenate.

3. The urine and tissues of the deficient animals were found to have a higher concentration of the vitamin than those of the control animals. The difference in enzyme synthesis was in the same direction, but was not statistically significant.

4. The results are interpreted as suggesting an increased requirement, by rats, of the vitamin in iron deficiency; this increased requirement is met by increased synthesis.

1. A survey of the incidence of goitre in Ceylon was carried out in the years 1947–9 and goitre was found to be endemic in the south-west sector of the Wet Zone of Ceylon.

2. In response to a request by the Ceylon Government to the World Health Organization for advice, Dr Dagmar Wilson in 1950 confirmed our earlier findings and as a short-term policy recommended the provision of iodine as KI tablets to the stress groups in the Wet Zone. This was initiated in August 1951.

3. A second survey was carried out in 1963 in nine of the villages in the Wet Zone that had been studied previously.

4. Statistical analysis showed that the incidence had significantly increased amongst the females in all nine villages and amongst the males in two villages.

5. A survey of the incidence amongst mothers attending antenatal clinics confirmed the existence of a strip of country where goitre was endemic.

6. The critical level of iodine intake from drinking water below which goitre becomes endemic has been shown to be 10 μg/1.

7. The low iodine content of the water in the Wet Zone has been shown to be due to the persistent heavy rainfall, associated with high drainage into the ocean, by which the soil is leached.

8. The mean annual escape of water per square mile of a river basin (the yield factor) has been shown to be directly proportional to the intensity of endemic goitre in that basin.

9. The aetiological factors related to the problem of goitre are discussed. The prophylactic method failed as it was not sustained.

10. Iodization of kitchen salt is recommended for use by the general population. The amount of iodine added to the salt should not be great enough to produce any side-effects. Potassium iodate is suggested as the most suitable source of iodine for use in tropical regions with high humidity.

1. The entry rates of urea into the urea pool of the body fluids have been measured in sheep given rations varying in crude protein percentage from 3.5 to 27.3.

2. Results obtained with a single injection and with continuous infusions of [14C]urea were essentially the same.

3. The difference between the entry rate and the rate of excretion of urea in the urine was taken to indicate the quantity of urea degraded in the alimentary tract.

4. Plasma concentrations and urea entry rates were significantly and linearly related.

5. The relationship between excretion rate and plasma urea concentration was best described by a cubic equation.

6. Degradation of urea in sheep was found to be extensive in all the animals studied; as the protein intake increased, the quantity of urea degraded also increased but the percentage of urea entering the body pool that was degraded was decreased. Animals given a ration containing 3.5% crude protein degraded 76–92% of the urea entering the body pool.

7. A rectilinear relationship was found between pool size and plasma urea concentration. The urea space in animals given low-protein rations was significantly less than in animals on high-protein rations.

8. The effects of starvation for 2, 4 and 6 days on urea metabolism in sheep were investi-gated. In a11 the sheep starved for 2 days there was a significant increase in urea pool size, but the entry rate was markedly depressed indicating a retention of urea in the body pool on starvation.

9. A significant amount of nitrogen was found to go through the system: rumen ammonia → portal blood ammonia→blood urea→rumen ammonia.

10.Urea excretion rate, urea clearance by the kidney, urine flow rate and the ratio of the concentration of urea in urine to that in plasma (urea U:P ratio) were also examined.

11. There were significant correlations between urine flow rate and urea excretion and between plasma urea concentration and urine flow rate.

1. Seventeen hooded female rats were given from weaning a retinol-free diet containing methyl retinoate. When 105 days old they were mated with normal bucks.

2. Six of these rats were subsequently given dietary supplements of 100 μg retinol daily and another six were given 100 μg 3-dehydroretinol daily. All twelve rats had litters.

3. The five rats that received only methylretinoate during pregnancy resorbed their foetuses.

4. One of the litters from the female rats given 3-dehydroretinol consisted of six male pups. These young rats had never had access to retinol. They were maintained on a retinol-free diet supplemented with methyl retinoate. Two of these rats were given daily supplements of 3-dehydroretinol and another pair were given daily an equal amount of retinol.

5. The six rats were killed when 195 days old. The testes and the retina of the rats given either 3-dehydroretinol or retinol were normal. The testes and the retina of the rats given methylretinoate only were degenerate.

1. In two experiments, 100 pigs were fed from age 4 or 5 weeks to age 16–19 weeks on practical-type diets containing 10% of meat meal (15–17% lipid) of either low (3–17) or high (114–150 μmoles/g lipid) peroxide value. The cereal basis of the diet in the first experiment was wheat and maize and in the second barley. Other variants were the inclusion of a stabilized vitamin E supplement in the diet of one of the groups in Expt 1, the presence of 100 (Expt1) or 250(Expt 2)ppm of copper, and storage of a diet containing oxidized meat meal for 6–21 weeks before feeding to one of the groups in Expt 2.

2. Apart from an unusually high incidence of stomach ulcers which, however, were almost equally distributed between the control and oxidized fat groups and did not appear to affect the health and nutrition of the animals, the pigs grew well, with no significant difference between the groups in weight gain, food conversion ratio, liver weight, vitamin A storage in the liver, and aspartate aminotransferase and alanine aminotransferase activities in the serum.

3. Changes in the lipids of the diets during storage were studied and samples of back fat from the carcasses examined for fatty acid composition, tocopherol content and susceptibility to autoxidation. Moisture content appeared to be a major factor influencing the oxidative stability of the meat meals used. Tocopherol content and oxidative stability of the pig fat were highest in the group given a vitamin E supplement, and generally lower in Expt 2 than in Expt 1.

1. After a preliminary period on pelleted perennial ryegrass hay (0.28% sodium in dry matter) groups of sheep were fed on timothy hay (0.04% Na) with and without added sodium chloride or sodium bicarbonate.

2. When the sheep were fed on timothy hay, the Na content of urine and faeces fell and balances were negative. Na content of saliva fell markedly and potassium content increased.

3. Supplementary N a prevented these changes.

4. The low levels of dietary Na appeared to have no effect on the well-being of the sheep.

1. The apparent digestibilities for chicks, operated on so as to allow separate collection of urine and faeces, of the nitrogen in a heat-damaged cod flour (C35) and of a control, freezedried cod muscle (C23) were 77 and 90% respectively.

2. The differences are similar to those found for rats in earlier work and considerably smaller than the differences found in nutritional value of the materials as sources of either lysine or methionine for chicks.

3. Chicks killed 3 h after a test meal containing C23 showed little more N in their small intestine than did those on a N-free diet; other chicks receiving C35 showed much more N remaining in the gut.

4. It is hypothesized that significant quantities of heat-damaged protein may remain undigested in the small intestine, but may then be de-aminated by fermentation in the caecum so that values for the digestibility of N and of individual amino acids may be misleadingly high.

5. This hypothesis is supported by the finding that in caecectomized chicks the apparent digestibility of the N of C35 was only 68%, whereas the digestibility of C23 remained the same as in intact chicks.

1. The interrelationships between dietary calcium, fluorine and vitamin D were studied in young rats.

2. Rats maintained on a low-Ca diet gained less weight and had less ash in their bones. Their femurs incorporated more radioactive Ca than those of rats kept on a control diet. Supplementation of the diet with F slightly decreased growth and the content of bone ash without any effect on the content of Ca and phosphorus in the bone ash. The F supplement decreased uptake of radioactive Ca by bone. Addition of vitamin D to a low-Ca diet improved growth and, when added alone, increased uptake of radioactive Ca by bone without affecting the content in femurs of ash, Ca or P. Addition of F to a low-Ca diet supplemented with vitamin D diminished the uptake of radioactive Ca.

3. Decrease of bone ash in rats fed the low-Ca diet was accompanied by an increase in bone nitrogen. The bones of the unsupplemented rats contained less citric acid per unit of dry, fat-free mass. Addition of F decreased citric acid, whereas addition of vitamin D increased it.

4. The results are discussed and it is concluded that vitamin D added to a low-Ca diet does not exert a calcifying effect on bone, but rather increases Ca turnover. F, on the other hand, reduces the exchangeability of bone mineral.

1. The concentration of copper in the liver of six African children suffering from marasmus has been compared with the values found for six children from the same area suffering from other diseases.

2. No significant difference was found in the concentration of Cu in the livers of children with marasmus compared with the values for the controls when the results were expressed either on a dry whole tissue basis or on a dry fat-free basis.

3. A highly significant difference was found in the concentration of Cu in the livers of children with marasmus when these values were compared, on a dry fat-free basis, with those found in an earlier study for children with kwashiorkor. The concentration of Cu in the livers of children with marasmus was twice that in the children with kwashiorkor.

1. Two experiments are described in which the effects of dietary fat on the synthesis of milk fat in the dairy cow have been investigated. In the first experiment a change-over design was used with two cows to study the effect of removing a mixed-oil supplement to a basal diet low in fat on the concentration and composition of plasma lipids and on the yield and composition of milk fat.

2. Reducing the dietary fat intake from about 430 to 170 g/day caused falls in the concentrations in plasma of phospholipid and of free and esterified cholesterol and, in one cow, also of triglyceride. The changes in composition and concentration of the fatty acids in the plasma triglyceride fraction also reflected changes in dietary intake of fatty acids. No effect of dietary fat intake on the total synthesis of milk fat was observed, but the composition of the milk fat reflected that of the dietary fat, and the yields of lauric, myristic, stearic and oleic acids were decreased in association with a decreased dietary intake of these acids.

3. In the second experiment the effect of supplementing a basal diet low in fat with either coconut, red palm or groundnut oil on the composition and yield of milk fat was studied in four cows using a 4 x 4 Latin square design balanced with respect to residual effects.

4. With each oil, increasing the dietary fat intake from about 100 to 400 g/day significantly increased the total yield of milk fat. Also, coconut and red palm oils significantly increased the fat content of milk, and groundnut oil the yield of milk.

5. With the exception of linoleic and palmitic acids, the increased dietary intake of the major fatty acids characteristic of the various oil supplements led to increased yields of these acids in the milk.