1. Rats 10 weeks old were fed for 9 weeks either on a stock diet containing 17% protein, or on a low-protein diet prepared from the stock diet with added glucose, minerals and vitamins. Half the animals on each diet were kept at room temperature (21°) and half in a cold environment (5°).

2. The calorie intake of the animals kept at 5° on both diets was 60–70% higher than that of the corresponding group at 21°. The animals on the stock diet and kept at 5° gained weight but not so much as those on the same diet at 21°. The animals kept on the low-protein diet at 21° lost weight, while those on the same diet at 5° lost only a little weight initially and none thereafter.

3. On both types of diet the liver, kidneys and gastro-intestinal tract weighed more per 100 g body-weight in animals kept in the colder of the two environments; the small intestine was conspicuous in this respect.

4. The weight of the fur was greater, and the weight of the skin less per 100 g body-weight at 5° than at 21°.

5. The animals on the stock diet at 21° had most fat in their bodies, both in absolute terms and per 100 g body-weight. There were no significant differences between the other three groups.

6. The skin of the animals kept at 5° had a significantly higher collagen to N ratio than the skin of those having the same diet at 21°.

1. The whole of the lower half of the small intestine, with the exception of the last few cm of the ileum, has been removed from sixteen suckling pigs, 3–4 kg in weight.

2. The operation is technically easy, but the exposure and handling of the intestines may produce crippling adhesions.

3. The postoperative management presents no serious nutritional difficulties.

4. If the operation is successful the animals become functionally normal, if slightly small, adults.

1. Studies were made of the effects of fermentation on the chemical composition and nutritive value of Idli, a product prepared from milled rice and dehusked black gram, and also of Khaman, a product prepared from dehusked and milled bengal gram.

2. Fermentation brought about an increase in thiamine and riboflavine contents and a decrease in phytate content in both materials.

3. Weanling rats fed on fermented Idli and Khaman were found to be superior to those fed on the corresponding unfermented product with regard to weight gain, nitrogen retention, thiamine and riboflavine contents of the liver and the activities of liver xanthine oxidase and succinic dehydrogenase and haemoglobin content of blood.

1. An investigation was made of the sequence of changes that occurred during the development of vitamin A deficiency in the chick. Particular attention was given to changes in the central nervous system (CNS) and in bone.

2. Groups of birds were killed after being fed the diet for 14, 17, 20, 22, 24 and 28 days. The tissues of five deficient and five control birds were examined unfixed for gross changes and photographed. Groups of five deficient and five control chicks were perfused through the heart with Heidenhainαs Susa solution and, after decalcification, the tissues were examined for gross and histological changes. The bones of other groups of five deficient and five control chicks were examined for tetracycline-induced fluorescence.

3. The first lesion seen was metaplasia of the nasal respiratory epithelium to a stratified squamous form. This was rapidly followed be decreased weight gain, the development of ataxia, compression of the CNS and Wallerian degeneration in the ventral and lateral columns of the cervical spinal cord.

4. Changes in bone were first seen in chicks killed 6 days after metaplasia of nasal respiratory epithelium and 3 days after ataxia and brain compression had been seen.

5. Changes were present in the epiphyseal cartilage zone of the femur and in the periosteum of the vertebrae, but not in the epiphyseal cartilage of the vertebrae. the changes in the femur were thought not to have a direct relationship to vitamin A deficiency and may have been produced by inanition.

6. An increase in osteoblast activity and cartilage formation was seen in the vertebral periosteum of the vitamin A-deficient chicks and the relationship of these changes to lesions in the CNS is discussed.

1. The effects of changes in zinc intake on weight gain, plasma Zn concentration and the development of clinical lesions of Zn deficiency have been studies in Zn depletion and repletion studies with calves and lambs.

2. A basal diet, the principal components of which are urea, dried egg white, starch, glucose, cellulose and arachis oil has been developed for trace element deficiency studies with ruminants.

3. Weight gain ceased abruptly in both calves and lambs when either the unsupplemented basal diet was given or when Zn supplements provided only 0.05 mg Zn/kg live weight per day. Mean plasma Zn concentrations in these animals fell from pre-experiment values of between 0.8 and 1.2 μg Zn/ml to below 0.4 μg Zn/ml after 1 week on these treatments.

4. Supplements providing 0.2 mg Zn/kg live weight per day were sufficient to maintain a good rate of growth but insufficient to prevent a fall in plasma Zn.

5. Growth arrest occurring within 2 weeks and a rapid fall in plasma Zn occurring within 1 week after Zn supplements were withheld from calves and lambs that had previously received 0.7 mg Zn/kg live weight per day for 6 and 14 weeks respectively indicated that these species have only a limited capacity to store Zn in a form that can be utilized during periods of inadequate Zn intake.

6. Tentative estimates are presented of the Zn requirements of calves maintained on this type of basal diet and the influence of ration composition of Zn availability is discussed.

7. The possible value and the limitations of plasma Zn determination as an aid to the field diagnosis of Zn deficiency are considered.

1. A micro-adaptation of the iodimetric method has been used to determine lipid peroxides in the tissues of vitamin E-deficient rats and chicks.

2. No increases in lipid peroxide were found in liver, kidney or adipose tissue of rats with nutritional liver necrosis due to deficiency of vitamin E and selenium. When liver necrosis was induced by giving rats a casein diet and silver acetate solution to drink, the peroxide value of the adipose tissue was not increased.

3. Degeneration of the testes of vitamin E-deficient rats was not accompanied by a rise in the peroxide value of the tissue lipids.

4. There was an increase in cathepsin activity of the kidneys of rats displaying the phenomenon of renal autolysis (post mortem), but there was no increase in lipid peroxide content.

5. No rise in lipid peroxide was found in dystrophic chick breast muscle, in cerebellum, brain and adipose tissue of chicks with encephalomalacia nor in the liver of chicks with exudative diathesis.

6. In rat liver, kidney, testis and leg muscle, peroxide values in the range 10–40 µ-equiv./g lipid were found, and these values were not altered either by a substantial change in the degree of unsaturation of the dietary lipid or by the addition of vitamin E to the diet. Dietary addition of N, N'-diphenyl-p-phenylenediamine (DPPD) or 6-ethoxy-1, 2-dihydro-2,2,4-trime-thylquinoline (ethoxyquin) also failed to affect the peroxide value of liver. The possibility that lipid peroxide is a normal metabolite of these tissues is discussed.

7. Peroxide values of rat adipose tissue were never found to be greater than 40 µ-equiv./g lipid and were readily decreased by the addition of vitamin E to the diet or by a decrease in the unsaturation of the dietary lipid. The peroxide content of this tissue may depend upon the up-take of peroxidized dietary lipid.

8. The conclusion from this study of true lipid peroxides in animal tissues is that the biological role of vitamin E is not connected with lipid peroxidation in vivo, in agreement with our previous studies on the metabolism of the fatty acid substrates of peroxidation and of α-tocopherol and other postulated biological antioxidants.

1. Liver necrosis was produced in rats given diets deficient in selenium and vitamin E and the metabolism of [5-Me-14C]D-α-tocopherol was studied during the development of the disease. 2. When a torula yeast diet (containing sufficient of the yeast to provide essential fatty acids) was used, the addition of 5 % cod-liver oil fatty acid methyl esters produced only a slight decrease in the time taken to produce the disease, compared to controls given methyl oleate; methionine had little protective effect. The metabolism of the radioactive tocopherol was unaffected by dietary lipid, Se or methionine and was not influenced by the development of necrosis. 3. When a casein diet (devoid of fat and containing insufficient Se to prevent liver necrosis) was used, the addition of small amounts of linoleic acid to the diet (as 2 % maize oil fatty acid methyl esters) decreased the time taken to produce the disease and increased its incidence. However, the metabolism of the radioactive tocopherol was independent of dietary lipid or Se. 4. It would appear that either Se or vitamin E may be necessary for effective utilization of the ratapos;s requirement for linoleic acid.

1. The relationship between the heart rate and the energy expenditure of four sheep, S6, S7, S8 and S1, was studies under conditions known to increase energy metabolism.

2. A close relationship between heart rate and energy expenditure was shown to exist in three of the four sheep tested when energy expenditure was increased by cold exposure and by increased levels of food intake.

3. The source and magnitude of the errors associated with this relationship were studied by analysis of the variation occurring in the O2 pulse (ml O2/heart beat) of the sheep in response to factors other than those directly related to changes in heart rate. In two sheep, S8 and S6, variations in O2 pulse were random. The errors associated with the estimation, from heart rate measurements, of the energy expenditure of these sheep were ±6.8% and ±8.1% respectively. In the other two sheep, S7 and S1, O2 pulse tended to vary significantly during the experiments, in a way that was not directly related to changes in heart rate. The errors of the relationship in these sheep were ±8.6% and ±13.8% respectively.

4. Indirect evidence was obtained to suggest that continuous measurements of heart rate continued to reflect with reasonable accuracy the energy expenditure of the three sheep, S6, S7 and S8 when they were standing and lying and when they were eating.

5. Direct measurements were made of the O2 consumption and heart rate of sheep S7 and S1 during the act of eating. The energy expenditure of sheep S7 estimated from its O2 consumption was close to that estimated from measurements of its heart rate. Large errors were noted between these two estimates in sheep S1.

6. It was concluded that sheep S8 and S6 would be suitable for long-term experiments designed to predict energy expenditure from heart rate measurements made in the field. Sheep S7 was considered to be of limited value for short-term experiments. Sheep S1 was considered to be unsuitable.