Milk, cheese, and butter : a practical handbook on their properties and the processes of their production, including a chapter on cream and the methods of its separation from milk / by John Oliver.

  • Oliver, John (Writer on dairy products)
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Milk, cheese, and butter : a practical handbook on their properties and the processes of their production, including a chapter on cream and the methods of its separation from milk / by John Oliver. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    of the supply. The roots suck up, in a dissolved state, the soluble foods, and these are subjected to a marvellous system of selection and transformation done by certain parts of the plant formative cells. These minute bodies consist of proto-plasm (meaning first form), a jelly-like substance ; but, though of so simple a character, they have powers which cannot fail to excite wonder and admiration. As the foods and the water which dissolves them come into contact with these cells in the movements of the sap, they are absorbed by them, and part or all are used as may be necessary. Even water is decomposed into the two gases H and O, when either or both of these are needed, for single or separate purposes, to combine with other elements in the life processes. Carbon is taken from H0CO3, S from HoSOj, and N from NH3 or HNO3. Now we see the value of the rotting roots and leaves, and straw of manures, and the use of applying manures which furnish other plant foods. The plant is very unlike the soil, but out of this it builds itself up, unconsciously, subject to the laws of the All-wise Creator. Almost all of the plant is constructed out of the five elements, H, O, C, N, and S, and their new combinations may be divided into two classes—{a) carbon and {b) nitrogen compounds. Carbon Compounds.—First among these are— Carbo-hydrates, in which C in 6 or 12 atoms is combined with H and O, these latter being always in the same proportion as in water. But it must not be supposed that the H and O are in the form of water, for they are properly combined with the C ; there are, however, cases in which extra quantities of them are present in a weaker association. They may be sub-divided as follows, viz :— Starches, of which the typical composition is C^HmOs, and‘of which the starch of the laundry is a familiar example, being obtained, from rice. Cereals and grasses contain starch in considerable propor- tions, and other plants have more or less of it. Cellulose, or the woody tissue of plants, and gums, has practically the same composition. Sugars, as found in fruits, the sugar cane, and beet-root, are of the same family. Fruit sugar has a composition of CgHioOu, and cane sugar of Ci^H^Pii, the difference between them being one proportion of and O more in two molecules of the former (-CiaHo40i3). But there is another—a physical—difference, for starch is insoluble, while sugar is soluble, as every tea-drinking washer- woman knows ; for, while sugar dissolves in her tea, the starch with which she stiffens linen only becomes a jelly. Starch, however can be converted into soluble sugar by the plant cells and certain processes referred to later. 13