OSMOND [1887] proposed the estimation of P by causing the formation of phosphomolybdic acid and its subsequent reduction to a blue com'pound which could be measured colorimetrically. Of the many variants of this procedure, that of Fiske & Subbarow [1925] has perhaps been the most widely adopted.2 They carried out the reduction in strongly acid solution (0.5N H2SO4) and used as reducing reagent a solution of I-amino-2-naphthol-4-sulphonic acid in sulphite-bisulphite mixture. The principal advantages claimed for the method were (1) rapidity of colour development; (2) proportionality between colour density and amount of P over a wide range; (3) relative freedom from interference by such substances as ammonium and iron salts, nitrates, nitrites, silicates and chlorides.King [1932] recommended the use of perchloric acid (final concentration 0.73N) in place of sulphuric acid in the method of Fiske & Subbarow. This facilitates the preliminary destruction of organic material necessary for the determination of total P. The solubility of barium and calcium perchlorates confers added advantages, e.g. in determinations on plant extracts which contain sufficient calcium to cause troublesome precipitates with sulphuric acid and on barium and calcium salts of phosphoric esters.The method of P estimation originally used by the author was a simple adaptation of King's perchloric acid method for use with an absolute photometer. An aliquot of the solution of orthophosphate3 under examination was placed in a 25 ml. volumetric flask, and to it were added 2 ml. 60 % perchloric acid, 1 ml. 8-3 % ammonium molybdate and 1 ml. reducing reagent (0.417 g. 1-amino-2-

I. For 26 weeks, adult male rats were fed on diets containing about 80 % of carbohydrate, given as dextrose, fructose, liquid glucose, or sucrose; their performance was compared with that of rats receiving a standard laboratory cubed diet (41 B) containing 60 % of carbohydrate, mainly as starch. 2. More of diet 41 B was eaten than of any of the diets containing sugars, but only with dextrose was the mean body-weight gain significantly lower than with diet 41 B.3. N o significant differences in body length or girth were produced by the different diets. 4.Compared with those of rats given diet 41 B, plasma cholesterol levels were significantly increased by fructose and sucrose and to a lesser extent by dextrose, but not by liquid glucose. 5.Compared with those given diet 41 B, the rats given fructose had heavier hearts, kidneys and livers, those given sucrose had heavier hearts and livers, and those given dextrose had heavier hearts. Those given fructose had the heaviest kidneys and livers, and heavier hearts than those given liquid glucose. The organ weights of those given liquid glucose and those given diet 41B were not significantly different. 6 . Compared with the values on diet 41B, carcass and liver fat were both significantly increased by sucrose and fructose but not by dextrose or liquid glucose. With fructose, liver fat was almost double that with dextrose or liquid glucose. 7. Dry-matter contents of whole carcass and liver followed substantially the same pattern as did the fat contents. 8. Liver protein content was significantly lower on the 80 yo carbohydrate diets. The reductions were greatest with fructose and sucrose. (Feyder, 1935;Bachmann, Haldi, Wynn & Ensor, 1938; Marshal1 & Womak, 1954;Macdonald, 1962bMacdonald, , 1963Macdonald & Braithwaite, 1964;Carroll, 1964) and there is now a substantial body of evidence that in a number of ways different kinds of dietary carbohydrate do produce different effects in both animals and man.Preliminary experiments (Allen & Leahy, unpublished) had shown minor betweentreatment differences in carcass and liver composition of male and female weanling and mature rats fed on diets containing 60 % of dextrose (D-glucose), liquid glucose or sucrose. T o emphasize these differences, further experiments, the results of which are now reported, were undertaken in which the carbohydrates studied formed about 80 % of the diet of adult male rats. At the same time the scope of the investigation was extended by including fructose as a fourth sugar, and rats in a fifth group were fed on a standard laboratory diet for comparison. The effects of these diets on body-weight, carcass dimensions, plasma cholesterol level, organ weights and carcass and liver composition were compared.https://www.cambridge.org/core/terms. https://doi

1. The variability in the purchase and consumption of vitamin C in the diet of people living in the United Kingdom has been studied using the Annual Reports of the National Food Survey Committee and new observations gathered independently.2. The sources of variability examined have been family household composition, social class, seasonal and week-to-week sampling variation.3. The distribution of mean household daily intakes of vitamin C approximates closely to a log-normal distribution. Assuming this to be so, it may be calculated that about one-quarter of households have vitamin C intakes averaging less than the 30 mg/person per day recommended by the British Medical Association Committee on Nutrition to provide a good margin of safety. Households with intakes below 20 mg/person per day may average 5% of the total. These percentages fall during the late summer and rise correspondingly in the remainder of the year.4. Allowing for the many uncertainties involved, it is suggested that up to 10% of households and an even greater proportion of individuals may have a vitamin C intake that is permanently below 30 mg/person per day.

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