The last two decades have seen a rapid expansion of State colleges of agriculture in the United States. The enrollment has increased rapidly and this has meant a rapid development in the means for offering resident instruction. The courses of study have been passing through a process of evolution coincident with this growth. In general it is largely true that the present-day curriculum of the agricultural college is an outgrowth of the old academic college course, resulting from a grafting of agricultural instruction on the old stock. This bulletin presents a study of the four-year course in agriculture leading to the degree of bachelor of science in the land-grant colleges of the 48 States of the United States. The study was undertaken in the effort to determine some of the fundamental principles on which the four-year course should be based. An addenda and index are included. (Contains 21 tables and 10 diagrams.) [Best copy available has been provided.]