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THE polymerization of glycerol to di-and tri-glycerol and to more highly polymerized glycerols has been described by a number of investigators, including Harris [1935], who has also prepared mixed esters of these polyglycerols with fatty acids. The large variety of esters which may be thus synthesized, though in many respects resembling fats, are distinguished by their wetting, emulsifying and other capillary-active properties, these being apparently related to the structure of the molecule in that it has a lipophilic group, in the form of a longchain fatty acid residue, and hydrophilic groups in the form of free hydroxyl at or near an end of the molecule. These surface-active functions of the polyglyceride esters are being utilized in various industries, and Harris [1933] describes their mechanism and suggests the use of these esters as emulsifying agents in edible emulsions. He also suggests their use in small percentages in margarine with the object of reducing the spattering of the margarine during frying. Because of the uniqueness of this group of compounds and their utility, it seemed of interest to investigate their utilization in the animal organism, the present report being principally concerned with growth and faecal excretion of fat. EXPERIMENTALAlbino rats were used, the stock in this laboratory being a pure inbred Wistar strain, reared under favourable conditions. The basic diet and the one fed to the controls consisted of ground Purina chow, to which was added a dried milk preparation (5 %), yeast (1 %) and water to proper consistency. For the experimental animals the basic ration was supplemented either with lard (5 or 10 %), or polyglycerol ester (5 or 10 %). In one large series of experiments the diet was begun soon after weaning (25-30 days old) and continued for as long as 14 months. Observations on over 100 rats revealed that both in the lard and polyglycerol ester-fed rats the rate of growth was normal or better than normal, the criterion for normal growth being that ofthe controls, which in our experience exceeded somewhat the standards obtained for the Wistar colony, as recorded by Greenman & Duhring [1931].Generally the lard-fed rats attained somewhat greater weights than the rats in the polyglycerol ester group, the difference being apparently related to the much greater accumulation of fat in the depots (perirenal, mesenteric, omental, genital etc.) in the former. Histological examination of the tissues disclosed no abnormalities in either of the experimental groups. Rats were maintained successfully on the polyglycerol ester and lard diets through three generations, ( 1938 )

No abstract

Owing to technical limitations a high degree of accuracy in the titrations cannot be expected in very low concentrations. Accordingly, as described by Smith and White, aberrant values are eliminated by plotting the experimentally determined values of C0/N2 and 1 /N. Those values of C0/N2 are disregarded which are not consonant with the majority and a value of Ca/N2 chosen to serve as a basic term of the series from which to calculate the successive values of P.

No abstract