What gives the value to these waste products is chiefly their nitrogen compounds.

Of late the importance of animal wastes, flesh, meal, dried blood, and fish has come to be understood, and a good many accurate experiments. have been made to test their digestibility, their nutritive value, and that of the manure produced from them. This will be explained in the following section, paragraphs 314-325. I will here only refer in few words to the results of a late series of experiments by Wildt, at Proskau, and by Kellner, at Hohenheim, with Norwegian fish guano fed to sheep. It appears that sheep digest the most of the nitrogenous material of the flesh, and a large part of that of the bone. What is not stored away in the body of the animal is excreted as urea, one of the most valuable forms of nitrogen for plant food. Only a small part of the phosphoric acid is digested, but the remainder is left in a very finely divided form, and hence much better for a manure. Kellner discusses the various methods employed for making the ingredients of fish more available for manure. Treatment with acid and caustic alkalies is unsatisfactory. Fermentation with urine is much better; but the most convenient and profitable way he concludes to be that of passing it through the digestive organs of domestic animals.

Practical conclusions.

313. One very great obstacle to the profit from using fish as manure is the fact that it contains only nitrogen, phosphoric acid, and lime, and does not supply the other soil ingredients of plant-food. Where potash is wanted the fish cannot suffice. Illustrations of this are only too abundant. I have only to look out of the window where I write to see in the distance a farm whose proprietor, some time ago, applied fish to one of his fields at the rate of nearly a ton to the acre, hoping to obtain a good crop of hay. In spite of this heavy and costly dressing the grass failed. At my suggestion he tried a series of experiments with different fertilizers to test the deficiencies of his soil. Wherever potash salts were used the crop was good; without potash it failed. The best results were obtained with a "complete" fertilizer, containing nitrogen, phosphoric acid, and potash, such as could be made from fish and potash salts. The recognition of facts like this often makes the difference between good profit and ruinous failure in farming.

nure.

The large amount of nitrogen in fish makes it a "stimulating" maIt helps crops to get more of the food contained in the soil, and thus to "exhaust" the immediately available supply. Farmers often complain that fish, like Peruvian guano, wears out their land. In Maine they talk of land that has been "herringed to death." In Connecticut we often see grasses leaving and sorrel coming in after such fertilizers are used. Some good farmers say their soil gets hard and "caked" after continuous use of fish. The remedies are, tillage and use of other manures, ashes, lime, potash salts, bone, yard manure, muck, and so on.

The nitrogen in fish makes it particularly good for grass and grain, but excess is apt to make grain "run to stalk" and lodge, and may injure or even kill any crop for which it is used.

Besides grain and grass crops, fish does well for corn, potatoes, garden vegetables, etc. It promotes the growth of tobacco, but is thought by many farmers to injure the quality of the leaf.

The fine, dry fish-guano with little oil is the best. The coarse, wet scrap is inconvenient to handle, and cannot be well diffused through the soil. Concentrated fertilizers ought to be thoroughly mixed with the soil so as to be accessible to the largest number of roots and injure none. Neglect to observe this causes immense waste of fertilizing materials and loss of crops. If the coarse scrap is to be used it is best to compost it. The lumps are thus divided, the material decomposed and changed to more available forms, its value for plant-food increased, and it can be applied so as to secure the greatest benefit with the least waste.

Fermentation with urine, as described above, improves fish greatly. The best method of all for getting fish into forms most fit for plantfood is to feed it to stock. This brings a two-fold advantage: it supplies the nitrogen (protein albuminoids) that poor foods, such as straw, cornstalks, and poor hay lack, and makes excellent fodder from cheap materials, while the nitrogen and phosphoric acid that are not used at the greatest possible profit to make flesh and bone are left in the manure in much better form for plant-food than they were in the fish.

There is great need of improvement in the manufacture of fish manures. What is wanted is a fine, dry product with as little ballast of water and oil and as much nitrogen as possible.

The chief obstacle to the better economizing of fish in agriculture is lack of information as to the best ways of making and using the prod ucts. To get this, careful scientific research and close practical obser vation are indispensable. Investigations in the laboratory and exper iments in the field combined will bring the needed knowledge, and it will be worth a hundred times the cost.

52. FISH AS FOOD FOR DOMESTIC ANIMALS.

Principles of animal nutrition.-European experiments.

314. Undoubtedly the manure problem is the most important that the agriculture of our older States has to solve. The next weightiest is the food question, how to best economize and improve our fodder materials. Inside this the most important special problem is how to obtain foods rich in nitrogen. Our feeding materials, taking them together, lack nitrogen. In consequence, our animals are insufficiently fed and fail to get the full benefit of the food they do have. The result is underproduction of meat, dairy products, and work, and in turn poor manure and poor crops. European farmers have passed through this costly

and bitter experience ahead of us, and have learned the cause and the cure. Necessity has driven them to study these problems in ways of whose cost, extent, and beneficent results we on this side of the water have as yet only a faint conception. Hundreds, we might almost say thousands, of feeding experiments have been made with horses, oxen, cows, sheep, goats, swine, and other animals. Some of the ablest chemists and physiologists in Europe are devoting their lives to these special investigations. Governments, universities, agricultural schools, societies, and private individuals are giving money by hundreds of thousands of dollars for the work. In the last ten or fifteen years investigation has been especially active. In twenty agricultural experiment stations, and in a large number of laboratories of universities and other schools, the studies are being carried on to-day, and already definite knowledge has been obtained which many thousands of farmers on the other side of the Atlantic are using to their profit, is beginning to come to us and will, with what must be added by our own efforts, prove of inestimable value to our agriculture.

The lessons our foreign brethren have learned so dearly are free to us if we are wise enough to take and use them. Their substance is briefly this:

The advanced agriculture of the present day looks upon the farm or the stable as a sort of manufacturing establishment. Domestic animals are the machines, food in the form of hay, grain, root crops, commercial food materials, &c., are the raw materials, and meat, milk, wool, labor, and progeny the products.

In cattle-feeding, then, the important question is, how, with the foods at hand or obtainable, to get the most valuable product with the least. outlay for raw material.

Feeding for maintenance and production.—Ingredients of foods and their functions.

315. Suppose that I have in my stable a cow, standing idle and giving no milk. She will require only food enough to supply the wastes resulting from the changes that are continually taking place in her internal organism, from the continual building over and renewal of all parts of her body. A certain amount of food of a certain quality is necessary, then, to maintain her in good "store" condition. This she will need to "hold her own" when nothing else is required of her.

But suppose that I demand of my cow production, say in the form of milk. For this purpose she will need more food. And, as everybody knows, the cow should have for the production of milk, not only a larger quantity, but also different quality of food from that which is needed for maintenance alone.

If, instead of milking my cow, I wish to fat her for the butcher, I shall also require production, but of still another sort, of fat and flesh. And if, instead of a cow, I have an ox that is to be kept at work, yet another

kind of production is required, muscular force. And I need not say that for these different kinds of production different kinds and amounts of fodder are requisite.

In the light of modern experimental science the maintenance of the animal and the production of meat, milk, heat, and force are not matter of so much hay, grain, and roots, but of the gluten, sugar, starch, fat, and so on, of which these are composed.

It has been already explained that animal and vegetable substances are composed of water, organic matters, and ash.

The following is, for instance, what is found in 100 pounds of wheat (grain):

Corn, hay, potatoes, in fact vegetables generally, contain nearly the same list of ingredients as wheat, but in different proportions. The same is true of animal foods. Meat and milk consist of similar ingredients.

For our present purpose we have to consider only the organic substance. Now notice in the table above that there is a distinction between two classes of ingredients of this organic substance of wheat. The gluten and fibrin contain nitrogen, while the sugar, starch, fiber, fat, &c., con tain no nitrogen.

This distinction between the nitrogenous and non-nitrogenous food ingredients is a fundamental one in economical cattle feeding.

Albumen, found pure in the white of an egg, is a representative of several kinds of substances, which consist chiefly of carbon, oxygen, hydrogen, and nitrogen. To these nitrogenous materials we apply the general name, albuminoids. The albuminoids are found in all animals. and plants. Muscle or lean meat, casein (curd) of milk, fibrin of blood, gluten, albumen, and fibrin of plants, are examples. Clover, beans, pease, oil-cake, are rich in albuminoids.

Again, there are other animal and vegetable materials that consist of carbon, oxygen, and hydrogen, simply. These are called carbohy drates and fats. Starch, sugar, gum, and cellulose or fiber are carbohy drates. The oily and fatty matters of plants as well as butter, tallow, &c., are fats. Potatoes, sugar-beets, fodder-corn, and straw are rich in carbohydrates and poor in albuminoids.

The distinctions between the ingredients of the animal tissues and

products are similar. Lean meat or muscle and the casein (curd) of milk, like the albumen of the egg, are albuminoid substances and contain nitrogen. The fat of the body and the fat (butter) in the milk, like the oils and fats of plants, contain no nitrogen.

The ingredients of the body are built up from those of the food. The nitrogenous materials, muscle, connective tissue, skin, &c., are formed from albuminoids. The carbohydrates and fats of the food, which have no nitrogen, cannot be transformed into nitrogenous tissues of the body. To form the fats, both the fats and albuminoids of the food contribute. A large part of the fat meat stored in the body and of the butter given off with the milk is made and must be made of the albuminoids of the food.

Just what work the carbohydrates do in the animal economy is not yet fully settled. They certainly cannot make flesh, and probably do but little at most to make fat. They act as fuel to keep up the animal heat, and doubtless contribute to the generation of muscular force. Just how much of the heat and force produced in the body comes from the consumption of albuminoids, how much from carbohydrates, and how much from fats is still an unsettled problem.

The animal has been compared to a machine. It is, however, a machine that must be kept running whether it produces anything or not. A horse, or cow, or sheep needs food even at rest in the stall. The machine is peculiar also in that it is wearing out continually and very rapidly, and consumes its own material for both fuel and repairs. The tissues of the body are all the while being used up and rebuilt. In the process of using up, heat and force are produced. The animal consumes food to make its flesh and fat and to give it warmth and strength, but it gets warmth and strength from the consumption of its own flesh and fat at the same time.

Now to make up for the continued wasting away of tissues and to maintain the supply of heat, food is necessary. But for this purpose but little of albaminoids is required. Carbohydrates will serve for fuel to keep the body warm. The horse or sheep at rest will get on with comparatively little nitrogen. Maintenance fodder may be poor in albuminoids if it furnish carbohydrates in plenty. Stock may be kept in the barn and even wintered on poor hay, cornstalks, and straw. But when production is required the case is very different. To make lean meat the animal must have albuminoids. Fat meat may be produced from the fat of the food, if there be enough, but practically a large part of the fat must come from albuminoids. The casein and fat (butter) of the milk likewise come from the albuminoids of the food, and for work also more or less of albuminoids are used. The growing colt or lamb, the working horse or ox, the milch cow and the fattening sheep or swine or steer must all have rich food and food rich in nitrogen. The nitrogenous ingredients, the albuminoids of the food, are its most important constituents. They may take the place of the carbo