Animal nutrition / [Thomas Barlow Wood].

  • Thomas Barlow Wood
Date:
1924
Catalogue details

Licence: In copyright

Credit: Animal nutrition / [Thomas Barlow Wood]. Source: Wellcome Collection.

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    sulphuric acid is added to sodium oleate, sodium sulphate is formed, and oleic acid is set free as an oily liquid. Fixed oils and fats always behave in this way when boiled with sodium hydrate, yielding soap and glycerol. They are com¬ pounds of glycerol with oleic or other more or less similar acids, which will be met with in the course of our work. We noted in our earlier experiments that oils dissolved in ether, and it is this property which enables us forSFafsPlantS f°r ^ie presence of oils in plants. Before testing, the plant substances must be dry and finely powdered. Shake with ether small quan¬ tities of linseed meal, oat meal, maize meal, and wheat flour in separate test-tubes. Filter through separate filters, and evaporate off the ether in each case over a vessel of hot water, being careful not to have a flame near, as ether and ether vapour are very inflammable. Note the amount of oil left behind in each case. Linseed contains much oil— over 30 per cent.—oat meal and maize meal much less—only about 5 per cent. Wheat flour contains only a trace. Transfer some of the oil in each case to a strip of filter paper, and note that it makes a greasy transparent mark which does not disappear on warming. The oils contained in linseed, oats, maize, and wheat are, therefore, fixed oils or fats which possess high food values.