Page:Encyclopædia Britannica, Ninth Edition, v. 16.djvu/323

Rh MILK 305 effect milk similarly concentrated, with a proportion of sugar added, and hermetically sealed in tin cans. The manufacture was transplanted to Switzerland in 1865, after which condensing factories were established in England, Ireland, Denmark, Bavaria, Norway, and elsewhere. &quot;With the introduction of the condensing trade there has also been associated the factory system of dealing with dairy products, by which the milk of many dairies is carried to one centre and dealt with either for condensing or for cheese or butter making. The following epitome of the process of condens ing milk is from a paper by Mr Willard of Cornell university, Now York (Jour. Roy. Agric. Soc., 2d series, vol. viii., 1872). The milk when received at the factory is first passed, he says, &quot; through a strainer to the receiving vat; from this it is conducted i- if, going through another strainer into the heating cans, each holding about 20 gallons ; these cans are set in hot water, and the milk is held in them till it reaches a temperature of 150 to 175 Fahr. ; it then goes through another strainer into a large vat, at the bottom of which is a coil of copper pipe, through which steam is conducted, and here the milk is heated up to the boiling point. Then the best quality of white granulated sugar is added, in the proportion of 1 j lb of sugar to the gallon of milk, when it is drawn into the vacuum-pan having a capacity of condensing 3000 quarts or more at a time. The milk remains in the vacuum-pan subjected to steam for about three hours, during which time about 75 per cent, of its bulk in water is removed, when it is drawn off into cans, holding 40 quarts each. The cans are only partially filled, and are then set in a large vat containing cold water, the water being of a height equal to that of the milk in the cans. Here it is stirred until the temperature of the condensed fluid is reduced to a little below 70; it is then turned into large drawing-cans with faucets, in order to facilitate the filling of the small cans, .... holding 1 lb each, which are immediately soldered to exclude the air.&quot; In the case of plain condensed milk the concentration is usually carried farther than is practised in preparing the preserved milk, it being evaporated down to between one-fourth and one-fifth of the original bulk. It is not put up in sealed tins, being intended for immediate use, and keeps sweet only for a few days, varying with the state of the weather, whereas the sugared milk in sealed cans keeps for years. The large amount, however, of cane sugar added to preserved milk seriously disturbs its balance of proportion as a perfect food, and renders it unfit to be used alone in a dilute state as a substitute for mother s milk by infants, a purpose for which it is largely employed. It should also be observed that the relative proportion of fat is small, the milk being partially skimmed before it is operated on, so that the statement that preserved milk diluted with a small proportion of water is equal to cream is not to be relied on. Preserved milk, rich in cream, has always a more or less rancid oily taste, and cannot be obtained so sweet and even in flavour as that largely deprived of fat. According to a German patent of E. Klebs in Prague, plain condensed milk may be preserved by adding to every 100 litres of the original milk a solution of 50 grains of benzoate of magnesium in one litre of water. Adulteration. Practically the invariable mode of sophisticating milk for sale consists in the addition of water and in the subtrac tion of cream, in other words, passing off skimmed or partly skimmed as new milk. Now and again there are found certain little refinements on these simple frauds, such as adding a quantity of sugar to correct the specific gravity, flour or starch to increase opacity, and a touch of colouring matter to cover the bluish tinge which would betray skimmed milk. In the United Kingdom no official standard of what constitutes pure milk has been promul gated, but the so-called Somerset House standard has been generally recognized in law courts. According to this, new milk should contain as a minimum of solids not fat 8 &quot;6 per cent, and of fat 2 - 5 per cent., and of water a maximum of 88 9 per cent. The most satisfactory manner of discovering the probable genuineness of a sample of milk is by chemical analysis carried sufficiently far to determine the amount of fat and of other solids present. Numerous attempts have been made to place in the hands of dairy men, dealers, and consumers of milk a trustworthy method of estimating the condition and value of the article by simple quantitive tests for cream or fat at once the most valuable con stituent and one the presence of which in average proportion is indicative of the quality of the whole. The simplest but at the same time the least trustworthy and efficient method is by means of the so-called &quot; creamometer,&quot; which consists merely of a graduated glass tube in which a measured amount of milk is placed and the amount of cream it throws up is read off by means of the scale. Specific gravity determinations have by themselves no significance, seeing milk deprived of its cream can by dilution with water be brought to correspond exactly with the original milk. But by a combination of two methods, first taking the specific gravity, next observing the yield of cream by the &quot; creamometer,&quot; and finally taking the specific gravity of the milk deprived of j cream, regard being had to the temperature of the milk in these j observations, an approximately accurate idea of the value of a ! sample may be obtained. Among so-called &quot;lactoscopes,&quot; the operations of which are based on the fact that milk rich in cream is a much more opaque fluid than that from which cream has been taken or to which water is added, that invented by Professor Feser of Munich is one of the simplest and most useful. It con sists of a glass tube open at the upper end and attenuated at its lower extremity. Into this narrower portion is fused a small cylindrical rod of opaque milk glass on which black lines are marked. These lines are invisible when the lower portion of the tube is filled with a measured quantity of milk, but on addition ol water they become visible. When the black lines become by the gradual admixture of water perfectly distinct, the richness of the milk in cream globules is indicated by the height to which the mixture of milk and water has risen in the wide portion of the tube, which has engraved on it a scale showing on one side the amount of water added and on the other the proportion of cream equivalent to the transparency resulting from such addition. Statistics. In the year 1878 it was calculated by Mr J. C. Morton that the total yield of milk from the 2,250,000 cows and heifers in milk or in calf in England and Scotland amounted to about 1,000,000,000 gallons yearly. He assumed that about one-sixth of that quantity (167,000,000 gallons) went to feed calves, and that the daily consumption of the population was 1,000,000 gallons, being rather more than a quarter of a pint per head, which accounts for 365,000,000, still leaving 468,000,000 gallons to be used for butter and cheese making. Two-thirds of this quantity, or 312,000,000 gallons, Mr Morton assumes was used for cheese-making, yielding 2,800,000 cwts. of cheese (rather less than 1 lb per gallon of milk), and the remainder, 156, 000,000 gallons, of milk devoted to butter-making would yield 530,000 lb of butter, or 1 tt&amp;gt; of butter for every 21 pints of milk. In these figures no account is taken of Ireland, whence at that period there were sent to England alone yearly 3,500,000 lb of salted butter. In June 1882 the number of cows and heifers in milk and in calf in Great Britain did not vary greatly from the number on which Mr Morton s estimate for 1873 was based, being 2,267,175, whilst in Ireland the number was 1,398,905, making the total for the United Kingdom 3,682,317. If we take approximately Mr Morton s data as the basis of calcu lation, the 3,682,317 milk cows and heifers in the United King dom would yield, at 440 gallons per head, 1,620,219,480 gallons of milk. Further, assuming that one-sixth of this is consumed by calves, one-third consumed by population, one-third used for cheese-making, and one-sixth used for butter-making, we have as the yield of cheese 4,846,000 cwts. and as the yield of butter 920,000 cwts. As Ireland is much more a butter-producing than a cheese-yielding country, the quantity of cheese made is probably overestimated in these figures, and the amount of butter made is correspondingly understated. To bring out the consumption of dairy products for the year the following imports must be added: Cwts. Value. Cheese 1 692 40 4,742,368 2,167,428 11,339,226 Thus we find the total supply of cheese to the United Kingdom in 1882 was 6,538,495 cwts., and of butter the supply was 3,087,428 cwts. Estimating the home produce of both articles at the same value as the imports, the cheese supply cost 18,320,000, and the butter 16,150,000. Adding to these the probable cost of the milk consumed as such (say 550,000,000 gallons at Is. per gallon = 27,500,000), we have for the year 1882 in round numbers 62,000,000 expended on dairyproduce within the United Kingdom. The total number of milch cows at present (1883) in the United States is stated at 15,000,000, which, taking the 440 gallons basis, yield annually 6,600,000,000 gallons, or nearly 30,000,000 tons of milk. In America the factory system of treating milk has attained much greater dimensions than in Europe, and that perfection of treatment, combined with the cheapness of raising and feeding stock, enables the American companies to enter the European markets with large quantities of cheese and other dairy products of uniformly good quality which find a ready and remunerative sale. Koumiss. Under this name is properly understood a fermented drink prepared from mare s milk by the Tartar tribes of the Russian empire and by all the nomad races of the northern parts of Asia. It is made by diluting mare s milk with about one-sixth part of its quantity of water, and adding as a ferment about one-eighth part of very sour milk or of old koumiss. This mixture is placed in a wooden vessel which is covered over with a thick cloth, and so left for about twenty-four hours in a moderately warm situation. During that time a thick coagulum rises to the surface, which is thoroughly reincorporated by churning. After standing for another day, the whole mass is again thoroughly churned and mixed up, and in this state it forms new koumiss, having an agreeable subacid taste. The liquor is mostly stored and preserved by the Tartars in skin bottles, in which the fermentation continues developing its alcoholic qualities, and mellowing and improving its taste. Genuine Tartar koumiss has the following composition : alcohol 3 21, lactic XVI. - - 39