The study of the suitability of various geographic areas for the growing of crops has been pursued along two lines: first, the investigation of the environmental requirements of species and varieties, and, second, the collection of environmental data in the area under study and making comparisons with other regions, especially by means of classifications. In order to serve agricultural needs more fully the agroclimatic-analogue, or homoclime, technique, in which parts of these two methods have been combined, has been developed for application to practical agronomic and horticultural studies. According to this technique similar ecologic or agroclimatic areas are delimited in different countries of the world by the comparison of all available climatological, geographic, and soils data. Areas in the United States have been used as the standard for comparisons. This is followed by the growing of genetically homogeneous strains of plants in the delimited analogous areas for the purpose of securing phenological records for checking the delimitations which were made by the use of physical data alone. This technique aids in the selection of plants for introduction into a region and will facilitate the effective distribution of new strains and reduce the waste of limited supplies of new material. Several countries are interested in this technique, and it would develop more rapidly in the United States with the cooperation of a number of agricultural stations as key testing stations, particularly for determining the ecological amplitude of new strains.

Leafy vegetables, frozen foods, and prepared baby foods were analysed for their content of nitrate. From the findings it is suggested that the nitrate in such foods may contribute to hemoglobinemia found in infants and may produce certain toxic, if not lethal, conditions in adults. The content of nitrate in the foods may be attributed in many instances to the application of nitrogenous fertilizers, especially nitrate of soda, to the growing crops.

Coffee plants (Coffea arabica L.) were grown in nutrient solutions for the purpose of studying deficiency symptoms of the following elements : nitrogen, phosphorus, potassium, magnesium, calcium, sulphur and iron. The methods employed in the growing of coffee plants in the nutrient solutions are described. After preliminary tests with several nutrient solutions Hoagland's formula was selected as most suitable for the present tests. However, the quantity of phosphate employed in the basic nutrient solution was reduced to one third of that given in Hoagland's formula. This reduction in phosphate was made because of the previous results obtained by Jacob which seemed to indicate that the coffee plant requires only very small amounts of phosphorus. In the present tests phosphorus deficiency symptoms were obtained and these results suggest that Jacob's failure to obtain phosphorus deficiency symptoms may be ascribed to use of Shive's solution, which has a very high phosphate content. While growing in this complete nutrient solution his plants may have stored enough phosphorus to supply their needs later when they were transferred to the solution lacking this element. In the course of the present investigation it was found that in the nutrient solutions containing KH2PO4 and having a pH higher than 5.5, the coffee plant absorbs insufficient iron. This difficulty of iron absorption by the coffee plants grown in nutrient solution was overcome by a technique previously described that is, when iron deficiency symptoms appeared on plants being tested for other deficiencies the nutrient solution was changed and the new solution used contained no phosphate. The plants were allowed to grow in this solution for two to four days and then the phosphate was added. In this way the plants absorbed sufficient iron for their requirements. The present paper describes and the color plates illustrate the symptoms on coffee plants that were associated, in the present studies, with nutrient solutions deficient in the various elements listed.