In its early classic period of over a half century ago agricultural chemistry was limited almost exclusively to a study of the fertilizer needs of crops; later the field of the science was widened so as to include the investigation of the needs of human and animal nutrition; still more recently the province of agricultural chemistry has been further extended so as to comprise any of the numerous applications of chemistry to the problems of agriculture and agricultural technology. In the present period of agricultural research the methods of attack are no longer exclusively chemical. It has long been recognized that success in this field cannot be attained by exclusive restriction to one particular branch of science. Many different sciences, as chemistry, physics, geology, mineralogy, botany, bacteriology, meteorology, biology, plant and animal physiology, engineering and economics are mutually involved. The active cooperation of experts who are trained in these various sciences is, therefore, essential for the solution of many of the problems which demand the attention of the various bureaus of the United States Department of Agriculture. It is because of this spirit of cooperation and coordination of effort that the scientific bureaus of the Department of Agriculture are the best equipped to solve many of the complex problems relating to crop and animal production.

The criticism has been made that the governmental scientific bureaus in some of their research activities are trespassing upon fields which belong more properly to universities or to industries and that in certain services which Federal agencies render there is a direct competition with trade and commercial organizations. The research work of the Bureau of Chemistry and Soils is not of the academic character which belongs to universities nor is it of the purely industrial character which belongs to manufacturing. Its investigations, although involving the technic and methods of pure research, have a direct bearing upon the practical problems of agriculture for which the Bureau was primarily organized. There is no duplication of effort with the research work of other Government bureaus or with that of State experiment stations, and there is no competition with commercial laboratories which are engaged in private consulting practice. The advisory services which the Bureau constantly renders to the fertilizer, food, tanning, vegetable-oil, cattle-feed, and other industries which utilize agricultural products are outside the field ordinarily covered by private commercial enterprise. When the Bureau has fully developed a new process for the utilization or handling of agricultural products, as in its processes for making furfural from agricultural wastes, of manufacturing starch from cull sweetpotatoes, of preparing byproducts from citrus fruits, or of preventing explosions and loss of life in the handling of dusty agricultural materials, the commercial development and practical application of these discoveries are immediately transferred to the interested industries. There is not only no competition with trade-consulting organizations, but the latter constantly call upon the Bureau for assistance and advice in connection with their own commercial problems.

ELEMENTARY AND ORGANIC CONSTITUENTS OF CROPS

The organization of the Bureau of Chemistry and Soils offers most excellent facilities for following the presence of beneficial and deleterious elements from their origin in the soils through various crops

to the final food products which are used for human and animal nutrition. Iodine and iron may be cited as examples of beneficial elements; fluorine and selenium as examples of deleterious elements. The demonstration of the importance of these and other hitherto neglected food constituents which occur in minimal traces of only a few hundredths of a percent has been one of the most important recent developments of agricultural chemistry. Because of the very small amount of some of these highly beneficial, or highly deleterious, elements the Bureau during the past year has given special attention to the perfection of methods of analysis that are sufficiently delicate to determine their presence in both soils and crops. This line of research is of the greatest importance to agriculture and the Bureau's researches in this field are being advanced as rapidly as its limited resources permit.

In addition to these elementary constituents, there is also a large number of organic substances which, although occurring in plant and animal products in exceedingly minute quantities, are yet of the highest physiological and nutritional value. Of primary importance among these organic substances which occur in plants and animals in almost infinitesimal amounts, are the vitamins. Without these vitamins life would be impossible for man or animal. Vitamin A, which occurs in codliver oil, and in the milk fat of all animals, is a highly important growth-promoting factor. Vitamin B, which occurs in yeast and the germ of grain, is necessary for the prevention of a nutritional disease known as beri-beri. Vitamin C, which occurs in citrus fruits, tomatoes, etc., is necessary for the prevention of scurvy. Vitamin D for the prevention of rickets, vitamin E, which occurs in the germ of grain, is necessary for preventing sterility, and vitamin C is necessary for the prevention of pellagra.

The valuation of foods for their content of vitamins constitutes an important part of the work of the Bureau of Chemistry and Soils, which has been delegated as the official distributing agency of the international vitamin standards for the United States. The effect of various agricultural and industrial practices, such as spraying, heating, drying, etc., upon the vitamin content of fruits and vegetables is an important subject that is being investigated by the Bureau in this connection.

Another group of fruit and vegetable substances which are insignificant as regards percentage but are of the highest importance are the fruit and vegetable pigments. Carotene, the yellow pigment of carrots, is very widely distributed in vegetables. It is a necessary constituent of the food of all herbivorous animals for it is the parent substance of vitamin A. The pigments of the apple, tomato, and other fruits are of great commercial importance because of their aesthetic appeal; fruits which are deficient in pigment have a much lower market value. Furthermore, a knowledge of the best means of preserving these easily destructible pigments in canned goods and other preserved food is highly desirable in order to produce the class of products which is most desired by the consumer. The Bureau's investigation upon vegetable pigments has won the heartiest commendation of the food industry.

Another group of highly important plant and animal organic substances of greatest importance to crops and animals are the enzymes which play an indispensible role in the processes of germina

tion, digestion, respiration and metabolism. The action of malted. grain in brewing, of yeast in fermentation, of rennet in making cheese and of pepsin and pancreatin in the digestion of food are familiar examples of enzyme action. Numerous illustrations can be given of their physiological and industrial importance. Many of these enzymes have a deleterious action because of their activity in producing rancidity, decay, and deterioration in foods and other agricultural products. The familiar darkening of apples and other fruits, when exposed to the air, is produced by enzymes, the action of which can be checked by certain inhibitors such as sulphur dioxide. It is for the prevention of this darkening that sulphur dioxide is used extensively in the dehydration of apples, apricots and other fruits. Because of the limitation imposed upon the presence of sulphur dioxide in food products by certain countries and the consequent impairment of our foreign market for dried fruit, the Bureau has given much attention during the past year to the finding of a harmless substitute for sulphur dioxide and has achieved a considerable degree of success. The application of this discovery to commercial practice is now being developed.

CHEMICAL CHANGES IN HANDLING CROPS

The chemical changes which crops undergo between the period of harvesting and utilization are responsible for immense losses to agriculture, and the prevention of such losses is a subject which is actively engaging the attention of the Bureau of Chemistry and Soils. The loss in the dry substance and nutritive value of hay between the period of cutting and feeding as a result of spontaneous heating and other changes has been shown by our investigations to exceed $50,000,000 a year in the United States. A great part of this loss can be prevented by keeping the moisture content of the cured below 30 percent. The Bureau has developed a rapid method for the control of moisture in hay. The loss of sugar in sugar cane during storage is another serious loss which the Bureau has shown can be largely prevented by keeping the cane sufficiently moist. The loss of starch in stored sweet potatoes is another problem of this character which is engaging the attention of the Bureau. The establishment of maturity standards for citrus and other fruits and the improvement of the color of fruits by means of ethylene are other examples of the Bureau's work in this field which has brought great profit to agriculture.

CHEMICAL UTILIZATION OF CROPS

The applications of chemistry to the utilization of crops so as to secure the best yield and best quality of product at a minimum expense is a general problem which has engaged the attention of the Department of Agriculture since the time it was established. provements in the manufacture of sugar from sugar cane and sugar beets; of table sirup from sugar cane, sorghum, and maple; of oil from the soybean and other oil-producing crops; of starch from sweetpotatoes; of inulin from chicory; of beverages from fruit juices; of canned goods from fruits and vegetables; and of turpentine and rosin from the southern pine are examples of the work which the Bureau of Chemistry and Soils is accomplishing in the field of crop utilization. In some cases, as in the manufacture of starch from sweetpotatoes, and in the preparation of fruit beverages, this work is leading to the

establishment of entirely new agricultural industries. In other cases, as in the improvement of methods for making sugar, table sirups, rosin, and vegetable oils, the Bureau's work has led to greatly increased profits for the farmer owing to the superior character of his products.

MANUFACTURE OF BYPRODUCTS FROM CULLS AND AGRICULTURAL WASTES

Closely related to the Bureau's work upon the chemical utilization of crops are its research activities upon the manufacture of useful byproducts from cull fruits and vegetables and from agricultural wastes such as straw, cornstalks, and other agricultural refuse. The Bureau's work upon the manufacture of citric acid, essential oils, pectin, and other byproducts from cull citrus fruits has been of immense profit to the citrus growers of California. The utilization of corncobs, hulls, and similar agricultural refuse materials for the manufacture of furfural has led to the establishment of an entirely new chemical industry. Of equal promise is the recent development of a process for manufacturing alpha-cellulose, which is used in enormous quantities by the rayon industry, from waste sugarcane bagasse. The Bureau is now developing this procedure in cooperation with the Hawaiian Sugarcane Planters Associatoin. The Bureau's recent work upon the manufacture of apple sirup and other byproducts from cull apples, which constitute about 10 percent of the total apple crop of the United States, has received very favorable commendation by the apple growers of the Northwest. The Bureau's work upon starch will help solve the problem of the utilization of cull sweetpotatoes which in some years exceeds 20 percent of the total crop. These culls. can be readily worked up with the sweetpotatoes which are specially grown for the production of starch.

As a result of the Bureau's work a number of sweetpotato starch factories are about to be erected in the South; the domestic starch thus produced will help to replace the large quantities of foreign starch (142,000,000 pounds root starch in 1932) which are imported each year into the United States. In this pioneer byproduct work of the Bureau a regional laboratory has been established at Ames, Iowa, in cooperation with the Iowa State College, for investigating the utilization of straw, cornstalks, cotton stalks, hulls, and similar waste materials for the production of paper, fiberboard, cellulose, organic chemicals, illuminating gas, decolorizing carbons and similar products. This work is accomplished under a specific congressional appropriation.

PREVENTION OF LOSSES TO AGRICULTURE BY INSECTS, FUNGI, FIRE,

DUST, EXPLOSIONS, ETC.

The losses to agriculture and the agricultural industries from these various destructive agencies probably exceeds $3,000,000,000 a year and the devising of means for reducing these immense losses has constituted one of the major activities of the Bureau of Chemistry and Soils. Only a very brief mention can be made of some of the Bureau's accomplishments in this field.

The Bureau has been actively engaged for a long period in research work upon the production of new insecticides, fumigants, repellants, etc., for reducing the colossal damage which is done each year to the

fruit, vegetable, cereal, textile, livestock, and other branches of agriculture by the attacks of insects both upon the farm and in the channels of commerce. Many of the new protective substances which the Bureau has devised for this purpose have found an extensive use and the public service patents which have been granted for the manufacture of such substances protect the public against their private exploitation. The insecticidal substances which are thus produced should be nonpoisonous to men and animals and the testing of the toxicity of these new products upon animals constitutes an important part of the Bureau's work in this connection.

In the case of arsenicals, fluorine compounds, etc., which are used as insecticides and are toxic to men and animals, the perfection of method, for removing the residual poisonous spray residues upon fruits, etc., by suitable washing fluids and devices is being thoroughly investigated. The Bureau's research work upon the new insecticidal substance rotenone, which is nontoxic to animals, has been of the greatest importance and has led to a vast increase tn the production of this compound. This work is leading to the growing of derris, cube, and other rotenone-producing plants and thus the work has an additional benefit to agriculture in stimulating the cultivation of new crops. The discovery of rotenone by the Bureau in Cracca virgineana (devil's shoestring) a common weed in many parts of the United States is of some significance in this connection. The Bureau's work in this field is performed in close cooperation with the Bureau of Entomology and Plant Industry. The loss to farm property in the United States for 1933 as a result of fires has been estimated to exceed $100,000,000, one fifth of this loss, or $20,000,000, being attributable to the spontaneous ignition of hay, straw, and other stored agricultural products. The investigation of the causes of spontaneous ignition and of the means for its prevention is being actively pursued by the Bureau. The various safety codes proposed by the Bureau for preventing farm fires have been adopted by insurance companies and the adoption of the protective recommendations of the Bureau, as in the case of fires in threshing machines and cotton gins, has led to a substantial reduction in the rates of insurance. In addition to the property loss by farm fires in the United States there is the heavy toll of human lives which is estimated at 3,500 persons annually. The Bureau's work upon farm fire prevention has thus an important humanitarian aspect.

The prevention of losses to property and life in industries which handle or process agricultural products as a result of dust explosions has been for many years an important activity of the Bureau of Chemistry and Soils. Among the industries thus affected may be mentioned grain elevators, flour and feed mills, sugar refineries, starch factories, and spice mills. Altogether some 28,000 plants and 1,325,000 persons are exposed to the hazards of this class. At its experimental plant in Arlington the Bureau conducts experiments upon a large practical scale in a special dust explosion gallery for the benefit of agricultural industries that are exposed to this particular danger. The Bureau's introduction of dust collectors, venting devices, inert gas in attrition mills and other protective devices has resulted in a great reduction of the losses to life and property from this cause. This work has a very wide commendation both from industry and from insurance companies who offer special reductions in insurance rates to those industries which have adopted the Bureau's codes.