In reading of the studies of soil fertility that were made by George Washington at Mount Vernon, we learn of the improvement that he made in the relatively poor soils of that area by growing plants of the legume family. The actual reason why such improvement was brought about was not known in Washington's time, but the results were apparent. Today, the value of legumes as soil builders is well recognized and we understand much more definitely than Washington did the reasons for their being so helpful in increasing crop production. Many soil areas do not contain the particular type of bacteria necessary to the fixation of atmospheric nitrogen by legumes. This is frequently the cause of failure in growing alfalfa, soybeans, cowpeas and less well known members of the legume family. Each legume has its own type of nodule-forming bacteria. In order to assure the presence of the proper bacterial family, means often must be employed to add them to the soil where the specific crop is to be grown. This may be accomplished by adding soil from an area where the legume does well to the new area, or the seed may be inoculated with commercial cultures before seeding. Either method is effective. If soil is used it should be drilled in or spread on a cloudy day to prevent the destructive action of the sun's rays on the exposed minute forms of plant life we call bacteria. If it is not known that the legume to be planted has been grown successfully in a given field within the previous several years, the precaution of adding the proper bacteria should be taken. In some sections, such legumes as red, alsike, crimson and white clovers have been grown for many years and the bacteria for these plants are well distributed. There, inoculation is not necessary for these crops, but it probably should be practiced if other legumes such as alfalfa, cowpeas or soybeans are to be grown on land for the first time. _The Value of Humus._--In addition to the chemical elements of plant food, all productive soils contain decaying vegetable matter, generally classified under the term "humus." Humus serves as a source of acid-generating material which further breaks down soil particles and, most important of all, serves as a food for millions of microscopic plants which develop and die quite beyond the scope of human vision. These constitute a type of bacteria which are distinctly beneficial and essential to human life since they make possible the growth of larger plants that serve as human food.