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air and soil. The organic matter required for growth and repair of tissues is protein, and the energy required for keeping the animal warm and for performing the functions of the organs and muscles is obtained by oxidation of organic compounds, mainly fat and carbohydrate. Protein in excess of that required for building new tissue or replacing waste tissue is also used as a source of energy, but protein foods are a more expensive source of energy than fat or carbohydrate, and they are generally used in a diet only in amounts necessary for tissue-building. Any excess of food over that required for growth and for energy is stored as fat. Not only must a diet contain protein, fat, and carbohydrates enough to furnish the necessary energy, but it must have a sufficient variety and amount of inorganic salts, and there are also certain other organic compounds, known as accessories or vitamines, which are present in small amounts in food from plant and animal sources and without which animals either do not grow or they develop certain diseases such as polyneuritis or scurvy, which are therefore known as deficiency diseases.

Energy requirements of animals have been carefully investigated by three methods: First, by determining the balance between the intake of energy in the food and the output in the excrement; second, by observing the amount of oxygen consumed during respiration and the amount of carbon dioxide exhaled; third, by direct measurement of the heat given off by the body in a calorimeter. The three methods are combined in experiments made with the respiration calorimeter devised by Atwater. By these means feeding standards have been established, especially by Armsby, for different animals under different conditions such as growing, working, fattening and giving milk.

Besides the importance of the required amount of different food substances it is now known that the quality of the protein has some effect on its availability for animal use. Work by Osborn has shown that some proteins do not furnish nitrogen in a form that can be used by growing or adult animals. Analyses of these proteins show them to be deficient in certain ones of the amino acids of which proteins are composed.

Carbon and Nitrogen Cycles.-The study of agricultural chemistry shows interesting cycles for carbon and nitrogen. Carbon is taken from the air as carbon dioxide by plants and synthesized into organic compounds which are then used by animals and returned to the air by oxidation during respiration or decomposition. Some carbon is returned to the air by plants by oxidation during respiration or decomposition or combustion, and there are other branches to the cycle, but in the main it may be represented as air-plant-animalair-plant- animal, etc.

In the same way combined nitrogen as nitrates is taken from the soil by plants and synthesized into organic compounds which are then used by animals and returned to the soil in manure or the dead body. Here also some of the nitrogen is returned to the soil by decaying plants, but the main cycle is soil-plant animal soil-plant animal, etc.

Dairy Chemistry- Dairying is an important agricultural industry not only commer

cially but also because dairy farming tends to keep the soil fertile by returning to it all the plant food taken from it except for the small amount used in producing the milk. Chemical investigations have been directed to the composition and character of milk from different cattle and under different conditions, to the chemical changes taking place during souring and curdling, to the processes of making butter and cheese and to the effect of pasteurization on the composition of milk.

Organizations.- Every State in the country now has an agricultural college or an agricul tural station where experiments in agricultural chemistry are carried on, and the United States Department of Agriculture is investigating many of the problems in this field. The Association of Official Agricultural Chemists, organized in 1880, is composed of the Federal and State officials who are enforcing the laws regarding foods, drugs, feeding stuffs, fertilizers, insecticides and fungicides, and those who are carrying on investigations along these lines under the Federal or State governments. The main work of this association is the improvement of the methods of analysis of agricultural products and it meets annually to report the results of collaborative work carried out on these methods. Its analytical methods are official in many of the Federal and State laws. The proceedings of the meetings and the methods of analysis are published in the Journal of the Association of Official Agricultural Chemists.

Bibliography.- Chamberlain, J. C., Organic Agricultural Chemistry) (1916); Fraps, G. S., Principles of Agricultural Chemistry' (1913); Hall, A. D., The Book of the Rothamsted Experiments' (1905); Hart, E. B., and Tottingham, W. E., General Agricultural Chemistry (1910); Hilgard, E. W., 'Soils' (1906); Ingle, Herbert, A Manual of Agricultural Chemistry) (1913); Kahlenberg, Louis, and Hart, E. B., Chemistry and Its Relations to Daily Life' (1913); Robertson, F. D, Practical Agricultural Chemistry' (1907); Snyder, Harry, The Chemistry of Plant and Animal Life (1913); Stoddart, C. W., The Chemistry of Agriculture for Students and Farmers (1915); Wiley, H. W., Principles and Practices of Agricultural Analyses' (190614); Journal of the Association of Official Agricultural Chemists; Journal of Agricultural Research; Bulletins of United States Department of Agriculture and of State Experiment Stations.

H. E. WOODWARD,

Bureau of Chemistry, Department of Agricul ture, Washington, D. C.

As a

AGRICULTURAL COLLEGES. result of National and State co-operation, which enables the ordinary farmer to profit from the experiments of widely separated individuals interested in scientific farming, the United States stands foremost in the matter of agricultural development. As far back as 1862 Congress passed the first of a series of acts whereby extensive grants of national lands were made and converted into trust funds for the support of at least one agricultural college in each State, the grants being contingent upon a certain percentage of assistance by the States. Our Department of Agriculture renders the greatest

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become an important factor in the middle West in developing the agricultural possibilities. Agriculture, engineering and general and household economics are taught to the students. There is a dairy, blacksmith-shop, foundry, machineshop, printing-office, and woodwork and painting shop connected with the college, where practical work can be followed by the students.

With agriculture as our leading industry, many of the large universities have in recent years established an agricultural course and experimental farms for work in the regular college course. When this subject is mentioned, one turns instinctively toward Cornell University, with its admirable agricultural and forestry departments; toward the Ohio State University, with its buildings and equipments aggregating nearly $5,000,000 and with an income of $1,250,000; or toward the University of Wisconsin or the University of California. These typical universities, which have given agriculture and horticulture a prominent place in their curriculums, send forth annually hundreds of students to teach practical farming to new communities which may still labor under the disadvantage of old methods and ideas of agricultural production. The Ohio State University at Columbus has over 2,500 students and a corps of 250 professors and assistants; but it aims to give a scientific and classical education to both young men and women. It is divided into six colleges, with one devoted to agriculture and domestic science and another to veterinary science. Students pursuing other studies can take courses in these departments, and there are also opportunities for graduate studies in the science of agriculture. There is a well-stocked farm connected with the university, a dairy department and a large laboratory for student work.

At the end of 1914 there were 69 State agricultural colleges, some of them being conducted in connection with the State universities. Their total endowments amounted to $60,000,000; the value of their farms amounted to $24,000,000 and their buildings to $51,800,000. Toward their maintenance the Federal Government was contributing $3,592,198 (see States Relations Service in article DEPARTMENT OF AGRICULTURE) and the States were contributing $17,997,765. The rest of their incomes, mostly from tuition fees, amounted to $13,301,000. The total number of students enrolled amounted to 115,054. During the four years from 1910 to the beginning of 1915 the increases in their equipment, faculties, student bodies, etc., have amounted to 67 per cent. During the year 1915 progress was especially notable; the State legislature of California appropriated large sums for additions to the group of agricultural buildings at the State University, Nebraska gave $100,000 for similar purposes and Cornell University completed a new Soils Building which cost $100,000.

AGRICULTURAL CREDIT ASSOCIATIONS. See Co-OPERATIVE BANKING; FEDERAL FARM LOAN ACT; LAND CREDIT.

AGRICULTURAL EDUCATION. See

EDUCATION, AGRICULTURAL.

AGRICULTURAL EXPERIMENT STATION. An institution for scientific research in agriculture. The modern agricultural experiment station owes its origin chiefly to the work of Boussingault and Liebig, born respectively in 1802 and 1803, although the earlier

work of Sir Humphrey Davy, De Saussure and others had prepared the way for that of these great chemists. During the third decade of the century Boussingault established and for a few years maintained a chemical laboratory on his farm, and there began the combination of field experiment with laboratory investigation which characterizes the experiment station of to-day.

In 1837 a young Englishman, John Bennett Lawes (q.v.), began making experiments in the use of bone superphosphate on his ancestral estate at Rothamsted, near St. Albans, Hertfordshire, about 25 miles northeast from London. The success of these experiments led him to engage in the manufacture of superphosphate and also stimulated a desire for further investigation, and after some years of preliminary work, in 1843 he associated with himself Dr. Joseph Henry Gilbert, a young chemist and a recent pupil of Liebig, and the two entered upon a systematic line of research which has been continued without material change of original plan until the present day. For more than half a century these two men worked together; both received the well-earned honor of knighthood, and before his death, which oc curred in 1900, Sir John Lawes made provision for the permanent continuance of the work, under what is now known as the "Lawes Agricultural Trust."

The feature of the work of Lawes and Gilbert which distinguished it from anything that had previously been undertaken, except the work of Boussingault, was the combination of systematic and long continued field and feeding experiments with parallel investigations conducted in the chemical laboratory, in which the principal agricultural plants adapted to the English climate were grown both continuously on the same land and in various rotations, the composition of the crops and of the soils upon which they were grown being determined from time to time, and in which large numbers of animals have been fed over long periods and under such conditions that it was possible to determine the chemical elements consumed in the food and the proportion of each utilized by the animal. Extensive detours have also been made into other fields of chemical research, especially that of the assimilation of nitrogen by plants. For many years several general assistants have been employed, including chemists, botanists, computers and other help. The entire expense of this work has been met by the originator, except that a chemical laboratory was presented to him some years ago in recognition of the value of his work.

In 1851 a small company of Saxon farmers, organized as the Agricultural Society of Leipzig, incited by the revelations of Liebig and Boussingault (q.v.), who were then in the full zenith of their work, employed a young chemist, Emil von Wolff, and started him in the experimental study of agricultural problems, especially those related to the feeding of animals.

In

a few years the government was induced to assume the cost of this work, and thus was established at Moeckern, near Leipzig, the first public agricultural experiment station in the world.

In the United States attempts at experimental research in agriculture were undertaken at the Agricultural High School, afterward State College, of Pennsylvania; at the Michigan Agri

cultural College and at the Maryland Agricultural College, all established between 1854 and 1858, and later several of the institutions organized under the National Agricultural College Act of 2 July 1862 undertook some investigations of this character.

The first regularly organized agricultural experiment station in America was established at Wesleyan University, Middletown, Conn., in 1875, under the directorship of Dr. W. O. Atwater, a young chemist who had become enthused with the idea while studying in Germany. For the inauguration of this work private initiative was necessary; Mr. Orange Judd, then editor and proprietor of the American Agriculturist, contributed $1,000 on condition that the State should appropriate $2,800 for the support of the station for two years. This offer was accepted and work was begun in October of that year. In 1877 at the expiration of this period the State assumed the entire support of the station, and it was removed to New Haven.

Similar stations were established by North Carolina in 1877; by New Jersey in 1880; by New York and Ohio in 1882; and by Massachusetts in 1883. During this period also several of the agricultural colleges organized their research work on a more definite basis, and by 1887 there were 17 stations in operation in 14 States.

In 1883 a bill was introduced in the House of Representatives of the National Congress by C. C. Carpenter, of Iowa, providing for the establishment of experiment stations in connection with the colleges of agriculture, but it was not voted upon. In the next Congress Mr. Cullen, of Illinois, introduced a bill providing for a grant of $15,000 annually to each State and Territory for this purpose. This bill was re-introduced in the following Congress by William H. Hatch, of Missouri, and after being so amended as to authorize States, in which experiment stations independent of the agricultural colleges had been previously established, to use the grant in support of such independent stations—a proviso applying to the five stations above mentioned the bill became a law on 2 March 1887.

Under this law experiment stations have been established in every State and Territory in the United States, 60 such stations being enumerated in 1914-the fund being divided between two stations each in Connecticut and New York; while additional stations have been established under State or Territorial support in Alabama, Louisiana, Missouri, New Jersey, Pennsylvania and Virginia, and in several of the States substations or test farms have been established under State support, but as adjuncts to the regular stations. In addition to these the National Government has established stations in Alaska, Hawaii, Porto Rico and Guam.

In 1914 the stations organized under the Hatch Act of 1887 and the Adams Act of 1906 (see below) had a total income of $5,054,687.96, of which $1,426,166.99 was received from the National Government, the remainder, $3,628,520.97, coming from State appropriations, fees, sales of produce and other sources. The stations employed 1,852 persons in the work of administration and research, and published 1,330 reports and bulletins, which were sent to over 1,000,000 addresses.

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The following are among the principal subjects under investigation by the American stations: (1) The soil: its physics, chemistry and biology; including tillage, drainage, irrigation and the maintenance of fertility by crop rotation and the use of manures and fertilizers. (2) The plant: its physiology, chemistry, nutrition and pathology; the introduction of new varieties; improvement in productiveness by selection and breeding; the control of fungous and bacterial diseases and injurious insects; the various phases of forestry. (3) Animals: the special adaptations of the various breeds; the chemistry of animal foods and the economics of feeding; dairying and its manifold problems; the control of animal diseases.

In addition to the work above outlined, several States have laid upon the stations certain lines of police work, such as the inspection of fertilizers, seeds, drugs, foods and animal feeding stuffs for the prevention of adulteration; that of live stock to prevent communication of animal diseases, and that of orchards and nurseries for the control of insect pests and fungous diseases; but such work is not scientific research; it frequently interferes materially with the conduct of such research, and is more properly an executive function of the State government. In some States it is so

recognized.

Under the provisions of the Hatch Act the stations are governed under the laws of their respective States, the National Government exercising no control except to make sure, through annual financial reports from the stations and through personal visits by officers of the Office of Experiment Stations of the Department of Agriculture, that the money appropriated by Congress is being expended for the purpose designated in the national law.

The stations, in connection with the colleges of agriculture, have organized an Association of American Agricultural Colleges and Experiment Stations, which meets annually at some point in the United States for the discussion of matters pertaining to their work, and the Office of Experiment Stations publishes a monthly journal, the Experiment Station Record, in which notices or summaries are given, not only of the publications of the American stations, but also of the scientific agricultural publications of the world.

While this work has been thus extending in the United States it has also spread over most of the civilized world, 728 such institutions being enumerated in other countries in a bulletin of the Office of Experiment Stations, published in 1904. The only countries in which experiment stations were not found in that year were Greece, China, Turkey, Russia, Afghanistan, Beluchistan, Mexico, Central America, Bolivia, Colombia, Ecuador, Patagonia, Peru, Uruguay and Venezuela. As was natural, there has been a decrease in the kind of activity which has characterized the European stations in normal times. The information available has been drawn on to a hitherto unprecedented degree. The forces of many of the stations have been drawn for the war and considerably depleted.

The European stations as a rule are confined to single lines of investigation, and very often to inspection work merely, whereas the American station generally embraces several co-ordinate departments, each with a chief and