Putnam patriot., 1914-06-26
THESIS ON MILK
The Analysis and Testing of Milk
By Gilbert Perry and Albert Pratt


 each person in the United States con sumes about 20 gallons el milk year, or family Of five uses about one quart B day. At present II is estimated bY the C \. Department Of Agriculture that the annual consumption Of milk per person Is about 50 gallons. About two.thifds of the milk produced is made into butter and cheese, the other third being consumed directly as milk and cream.
 Since milk is of such great import ance as q food, it is necessary for each and every person 10 be familiar with the care and management Of cows in- eluding the different kinds Of feed, the composition of milk, the manufacture of dairy products, the distribution and marketing of milk, also with the study of the digestibility and nutntive value of milk. To secure this end many ex. pefiments and investigations have been carried out by the different Ex- pertinent Stations in the L. S. Depart ment of Agriculture, and by different colleges and chemists.
 The word milk as we understand it generally means cows milk, since cows can be made to produce the best results for given amount of feed and care. But milk from other animals is just as nutritious and is used in some countries. For example, goats milk Is very common in the hilly regions of Europe. Butlalo's is used in India, while mares milk Is used extensively on the steppes of Russia and in Cen. tral Asia.
 Perhaps no food has been more often tested by chemists than milk, and es a result one may easily obtain great deal of information regarding the conn position and properties ol milk and it's constituents. The components of milk are numerous and in different prop9r. tions III different kinds of cows milk. They may be divided into five classes as follows: tl1 water, t21 fats, j3l al. buminioids or substances containing nitrogen, n sugar, and 5) ash.
 As figures show, milk k sort of a dilute solution since 1t contains n large percentage of water. According to ex- periments the average composition Of milk k 57 percent. of water.
 Milk as it k drawn from the COW is familiar to all. It is whitish liquid which varies in appearance and in taste. 1t Is commonly described as thin, somewhat transparent, whilish liquid called the plasma in which floats very tiny giobues of fat, so nu. mefous that milk appears to be a white liquid.
 The fats in milk are in two classes, the volatile and the non-volatile in- cluding mixture of several types of separate and distinct fats. The vole. tile fats are Of very small proportion to the total amount of fats, about h per cent. They are the oils which give to milk it's odor and flavor, the chief of which being butyrin. These volatile fats are derived directly from the food and sometimes give undesirable fiaVors to the milk. The characteristic flavors due from grass, clover, and like feed k highly esteemed while those due from such feeds as turnips, onions, and cab. bage are not so desirable If care is taken 10 arrange the feeding and milk. ing of the COW about ten or twelve hours after such food as cabbage Is giv. en, the milk will not have the unde- sirable taste.
 The non.Volatile fats make up about s5 percent of the total amount of fats They are mixture of several fats, the chief ones being olein and palmitin Olein is in different proportions in diff ferent samples and upon the amount of Il depends the hardness CT softness of the fats. The fat exists in the milk Rs very small globules from ll500 to l25000 of an inch in diameter. The palmitin furnishes the eoloung matter of the fats.
 Test for Fats
 Determination of the Per Cent of Fat by the Babcock Method.
 This method consists in adding strong sulphuuc acid 10 the milk 10 dissolve all of the solids except the fat, which is afterwards separated by means ei the eenlfHeal machine.
 kigst We obtained some milk and mixed t thoroughly by pouring it from one vessel to another. Then We filled the milk pipette by placing the lower end in the milk and sucking at the upper end until the milk rose above the mark indicated on the stem, which was l7.6 co. Then placed my finger over the pipette and by slightly rais. ing the finger 1 allowed the milk To run slowly into the test bottle.
 We filled the graduate up to l7.5 cc. mark with sulphutie acid l5g. l.S2) and poured this into the test bottle hy holding the bottle in an inclined posi-. tion So lthat the acid ran down the neck of the bottle and did mol come into contact with the milk too abrupt ly, thus eharring il.
 Then we shook the bottles in rota- ting motion so thai the acid and the milk would mix properly. The solu. lion at first appeared nearly coloile,s, because of the large amount of heat evolved by the chemical action but soon changed to very dark brown,