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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    and only the partial recombination of their elements, there remain three gases in a free state—viz., N, O, and CO^—estimated at from .i to .3 per cent, of newly-drawn milk. The N is in by far the largest quantity, about |ths of the whole, as shown by analysis, the O about ith, and the CO^ covering the balance. It is useless to attempt any definite figures, because the causes of their presence are con- tinually varying ; and as they are soon lost to the milk, they are not of great consequence. The presence of alkaline substances gives to new milk a reaction of the same kind, while the COo originally in it, with some probably absorbed by it during milking, and acid phosphates—if such are pre- sent,—give it an acid reaction. This makes the milk both alkaline and acid at the same time, and this double character is called the ampho- teric reaction. This tends to mislead the dairyer when testing such milk for condition. The alkalinity of new milk is increased by heating, because the COo is driven off. Finally, there is the oil of milk, a volatile essence, which can be dissolved out with ether, and is believed to be the cause of the natural odour of new milk. Such, then, is milk as given by the cow. In the accompanying diagram the original elements are displayed in line 2, and from these a series of lines lead to the secondary combinations in line 3, and the final ones in lines i and 4.