Agriculture for Beginners Part 31
[Ill.u.s.tration]
SECTION LXII. HOW MILK SOURS
[Ill.u.s.tration: FIG. 273. MICROSCOPIC APPEARANCE OF PURE AND IMPURE MILK At the left, pure milk; at the right, milk after standing in a warm room for a few hours in a dirty dish, showing, besides the fat-globules, many forms of bacteria]
On another page you have been told how the yeast plant grows in cider and causes it to sour, and how bacteria sometimes cause disease in animals and plants. Now you must learn what these same living forms have to do with the souring of milk, and maybe you will not forget how you can prevent your milk from souring. In the first place, milk sours because bacteria from the air fall into the milk, begin to grow, and very shortly change the sugar of the milk to an acid. When this acid becomes abundant, the milk begins to curdle. As you know, the bacteria are in air, in water, and in barn dust; they stick on bits of hay and stick to the cow. They are most plentiful, however, in milk that has soured; hence, if we pour a little sour milk into a pail of fresh milk, the fresh milk will sour very quickly, because we have, so to speak, "seeded" or "planted" the fresh milk with the souring germs. No one, of course, ever does this purposely in the dairy, yet people sometimes do what amounts to the same thing--that is, put fresh milk into poorly cleaned pails or pans, the cracks and corners of which are cozy homes for millions of germs left from the last sour milk contained in the vessel. It follows, then, that all utensils used in the dairy should be thoroughly scalded so as to kill all germs present, and particular care should be taken to clean the cracks and crevices, for in them the germs lurk.
In addition to this thorough cleansing with hot water, we should be careful never to stir up the dust of the barn just before milking. Such dusty work as pitching hay or stover or arranging bedding should be done either after or long before milking-time, for more germs fall into the milk if the air be full of dust.
To further avoid germs the milker should wear clean overalls, should have clean hands, and, above all, should never wet his hands with milk.
This last habit, in addition to being filthy, lessens the keeping power of the milk. The milker should also moisten the parts of the cow which are nearest him, so that dust from the cow's sides may not fall into the milker's pail. For greater cleanliness and safety many milkmen curry their cows.
The first few streams from each teat should be thrown away, because the teat at its mouth is filled with milk which, having been exposed to the air, is full of germs, and will do much toward souring the other milk in the pail. Barely a gill will be lost by throwing the first drawings away, and this of the poorest milk too. The increase in the keeping quality of the milk will much more than repay the small loss. If these precautions are taken, the milk will keep several hours or even several days longer than milk carelessly handled. By taking these steps to prevent germs from falling into the milk, a can of milk was once kept sweet for thirty-one days.
The work of the germ in the dairy is not, however, confined to souring the milk. Certain kinds of germs give to the different sorts of cheeses their marked flavors and to b.u.t.ter its flavor. If the right germ is present, cheese or b.u.t.ter gets a proper flavor. Sometimes undesirable germs gain entrance and give flavors that we do not like. Such germs produce cheese or b.u.t.ter diseases. "Bitter b.u.t.ter" is one of these diseases. To keep out all unpleasant meddlers, thoroughly cleanse and scald every utensil.
EXERCISE
What causes milk to sour? Why do unclean utensils affect the milk?
How should milk be cared for to prevent its souring? Prepare two samples, one carefully, the other carelessly. Place them side by side. Which keeps longer? Why?
SECTION LXIII. THE BABc.o.c.k MILK-TESTER
It is not sufficient for a farmer or a dairyman to know how much milk each of his cows yields. He should also know how rich the milk is in b.u.t.ter-fat. Wide-awake makers of b.u.t.ter and cheese now buy milk, not by the pound or by the gallon, but by the amount of b.u.t.ter-fat contained in each pound or gallon of milk. A gallon of milk containing four and a half per cent of fat will consequently be worth more than a gallon containing only three per cent of fat. So it may happen that a cow giving only two gallons of milk may pay a b.u.t.ter-maker more than a cow giving three gallons of milk. Of course it is easy to weigh or measure the quant.i.ty of milk given by a cow, and most milkers keep this record; but until recent years there was no way to find out the amount of fat in a cow's milk except by a slow and costly chemical test. Dairymen could only guess at the richness of milk.
In 1890 Dr. S. M. Babc.o.c.k of the Wisconsin Experiment Station invented a wonderful little machine that quickly and cheaply measures the fat in milk. Few machines are more useful. So desirous was Dr. Babc.o.c.k of helping the farmers that he would not add to the cost of his machine by taking out a patent on his invention. His only reward has been the fame won by the invention of the machine, which bears his name. This most useful tester is now made in various sizes so that every handler of milk may buy one suited to his needs and do his own testing at very little cost.
The operation of the machine is very simple. Suppose that the members of the cla.s.s studying this book have been asked to take a Babc.o.c.k machine and test the milk of a small herd of cows. They can readily do so by following these directions:
While the milk is still warm from the first cow to be tested, mix it thoroughly by pouring it at least four times from one vessel to another.
A few ounces of this mixed milk is then taken for a sample, and carefully marked with the name of the cow. A number is also put on the sample, and both the cow's name and the number entered in a notebook. A small gla.s.s instrument, called a pipette, comes with each machine. Put one end of the pipette into the milk sample and the other end into the mouth. Suck milk into the pipette until the milk comes up to the mark on the side of the pipette. As soon as the mark is reached, withdraw the pipette from the mouth and quickly press the forefinger on the mouth end. The pressure of the finger will keep the milk from running out.
Then put the lower end of the pipette into one of the small long-necked bottles of the machine, and, lifting the finger, allow the milk to flow gently into the bottle. Expel all the milk by blowing through the pipette.
The next step is to add a strong, biting acid known as sulphuric acid to the test-bottle into which you have just put the milk. A gla.s.s marked to show just how much acid to use also comes with the machine. Fill this gla.s.s measure to the mark. Then pour the acid carefully into the test-bottle. Be sure not to drop any of the acid on your hands or your clothes. As the acid is heavier than the milk, it will sink to the bottom of the bottle. With a gentle whirling motion, shake the bottle until the two fluids are thoroughly mixed. The mixture will turn a dark brown and become very warm.
Now fill the other bottles in the same way with samples drawn from different cows. Treat all the samples precisely as you did the first. Do not forget to put on each sample the name of the cow giving the milk and on each test-bottle a number corresponding to the name of the cow.
You are now ready to put the test-bottles in the sockets of the machine.
Arrange the bottles in the sockets so that the whirling frame of the machine will be balanced. Fit the cover on the machine and turn the handle slowly. Gradually gain in speed until the machine is whirled rapidly. Continue the turning for about seven minutes at the speed stated in the book of directions.
After this first turning is finished, pour enough hot water into each test-bottle to cause the fat to rise to the neck of the bottle. Re-cover the machine and turn for one minute. Again add hot water to each bottle until all the fat rises into the neck of the bottle and again turn one minute.
There remains now only the reading of the record. On the neck of each bottle there are marks to measure the amount of fat. If the fat inside the tube reaches only from the lowest mark to the second mark, then there is only one per cent of fat in this cow's milk. This means that the owner of the cow gets only one pound of b.u.t.ter-fat from each hundred pounds of her milk. Such a cow would not be at all profitable to a b.u.t.ter-seller. If the fat in another test-bottle reaches from the lowest mark to the fourth mark, then you put in your record-book that this cow's milk contains four per cent of b.u.t.ter-fat. This record shows that the second cow's milk yields four pounds of fat to every hundred pounds of milk. This cow is three times more valuable to a b.u.t.ter-maker than the first cow. In the same way add one more per cent for each higher mark reached by the fat. Four and one-half per cent is a good record for a cow to make. Some cows yield as high as five or six per cent but they do not generally keep up this record all the year.
[Ill.u.s.tration: FIG. 274. BABc.o.c.k TESTER AND HOW TO USE IT The tester, acid, acid measure, test-bottle, and thermometer at bottom; filling the pipette on right; adding the acid and measuring the fat at top]
The Babc.o.c.k tester shows only the amount of pure b.u.t.ter-fat in the milk.
It does not tell the exact amount of finished b.u.t.ter which is made from 100 pounds of milk. This is because b.u.t.ter contains a few other things in addition to pure b.u.t.ter-fat. Finished and salted b.u.t.ter weighs on an average about one sixth more than the fat shown by the tester. Hence to get the exact amount of b.u.t.ter in every 100 pounds of milk, you will have to add one sixth to the record shown by the tester. Suppose, for example, you took one sample from 600 pounds of milk and that your test showed 4 per cent of fat in every 100 pounds of milk. Then, as you had 600 pounds of milk, you would have 24 pounds of b.u.t.ter-fat. This fat, after it has been salted and after it has absorbed moisture as b.u.t.ter does, will gain one sixth in weight. As one sixth of 24 is 4, this new 4 pounds must be added to the weight of the b.u.t.ter-fat. Hence the 600 pounds of milk would produce about 28 pounds of b.u.t.ter.
EXERCISE
1. Find the number of pounds of b.u.t.ter in 1200 pounds of milk that tests 3 per cent of b.u.t.ter-fat.
2. A cow yields 4800 pounds of milk in a year. Her milk tests 4 per cent of b.u.t.ter-fat. Find the total amount of b.u.t.ter-fat she yields.
Find also the total amount of b.u.t.ter.
3. The milk of two cows was tested: one yielded in a year 6000 pounds of milk that tested 3 per cent of fat; the other yielded 5000 pounds that tested 4 per cent. Which cow yielded the more b.u.t.ter-fat? What was the money value of the b.u.t.ter produced by each if b.u.t.ter-fat is worth twenty-five cents a pound?
CHAPTER XII
MISCELLANEOUS
SECTION LXIV. GROWING FEED STUFFS ON THE FARM
Economy in raising live stock demands the production of all "roughness"
or roughage materials on the farm. By roughness, or roughage, of course you understand that bulky food, like hay, gra.s.s, clover, stover, etc., is meant. It is possible to purchase all roughage materials and yet make a financial success of growing farm animals, but this certainly is not the surest way to succeed. Every farm should raise all its feed stuffs.
In deciding what forage and grain crops to grow we should decide:
1. The crops best suited to our soil and climate.
2. The crops best suited to our line of business.
3. The crops that will give us the most protein.
4. The crops that produce the most.
5. The crops that will keep our soil in the best condition.
1. _The crops best suited to our soil and climate._ Farm crops, as every child of the farm knows, are not equally adapted to all soils and climates. Cotton cannot be produced where the climate is cool and the seasons short. Timothy and blue gra.s.s are most productive on cool, limestone soils. Cowpeas demand warm, dry soils. But in spite of climatic limitations, Nature has been generous in the wide variety of forage she has given us.
Our aim should be to make the best use of what we have, to improve by selection and care those kinds best adapted to our soil and climate, and to secure, by better methods of growing and curing, the greatest yields at the least possible cost.
2. _The crops best suited to our line of business._ A farmer necessarily becomes more or less of a specialist; he gathers those kinds of live stock about him which he likes best and which he finds the most profitable. He should, on his farm, select for his main crops those that he can grow with the greatest pleasure and with the greatest profit.
[Ill.u.s.tration: FIG. 275. FILLING THE BARN WITH ROUGHAGE FROM THE FARM]
The successful railroad manager determines by practical experience what distances his engines and crews ought to run in a day, what coal is most economical for his engines, what schedules best suit the needs of his road, what trains pay him best. These and a thousand and one other matters are settled by the special needs of his road.
Ought the man who wants to make his farm pay be less prudent and less far-sighted? Should not his past failures and his past triumphs decide his future? If he be a dairy farmer, ought he not by practical tests to settle for himself not only what crops are most at home on his land but also what crops in his circ.u.mstances yield him the largest returns in milk and b.u.t.ter? If swine-raising be his business, how long ought he to guess what crop on his land yields him the greatest amount of hog food?
Should a colt be fed on one kind of forage when the land that produced that forage would produce twice as much equally good forage of another kind? All these questions the prudent farmer should answer promptly and in the light of wise experiments.
3. _The crops that will give us the most protein._ It is the farmer's business to grow all the gra.s.s and forage that his farm animals need. He ought never to be obliged to purchase a bale of forage. Moreover, he should grow mainly those crops that are rich in protein materials, for example, cowpeas, alfalfa, and clover. If such crops are produced on the farm, there will be little need of buying so much cotton-seed meal, corn, and bran for feeding purposes.
4. _The crops that produce the most._ We often call a crop a crop without considering how much it yields. This is a mistake. We ought to grow, when we have choice of two crops, the one that is the best and the most productive on the farm. Average corn, for instance, yields on an acre at least twice the quant.i.ty of feeding-material that timothy does.
5. _The crops that will keep our soil in the best condition._ A good farmer should always be thinking of how to improve his soil. He wants his land to support him and to maintain his children after he is dead.