It is suggested that those who are really interested in prices should fill in month by month in the blank tables the figures as they become available. Sources of current figures are the Market Reporter, published weekly by the United States Department of Agriculture; the daily live stock papers published at the great central markets; the Monthly Crop Reporters, published by the United States Department of Agriculture, and, so far as retail prices are concerned, the monthly publications of the Bureau of Labor Statistics. It is hoped that eventually the Bureau of Markets of the United States Department of Agriculture will have available exceedingly valuable figures. At present, however, the Bureau of Markets figures are practically worthless because they have not been continued long enough to have sufficient background to enable anyone to judge them properly. The effort has been made in the prices here collected to cover the period immediately preceding the war quite thoroly, in order that those who are interested may work out normal pre-war relationships. In all price questions, the problem of grade is involved. Gradually the grade classifications have been made more and more scientific, but even to this day there is haziness in certain products, notably cattle. It is believed, therefore, that the cattle prices are more unreliable than any other. Scientific grading of cattle is possible, and will be adopted as soon as the producers are in position to demand it. Market figures furnish the laboratory of economics. It is believed that it is as essential for students at agricultural colleges to do laboratory work in economics as it is for them to spend such a large part of their time in the chemical, zoological or botanical laboratories. When the agricultural students judge marketable live stock, it is suggested that they be required to estimate the weight, grade, dressing percentage and probable Chicago price. An ingenious teacher, who is familiar with economics and market grades of grain and live stock, can think of many devices to bring home to his students the fact that the market is a living thing, yet subject to certain laws which are almost as exact as Mendel’s law of inheritance. The author will appreciate being informed of any mistakes in the figures. Great pains have been taken to make them accurate, but it is inevitable that a few mistakes will creep in. * * * * * The following gives a description of grades and sources of information for some of the products for which figures are given in the tables of the Appendix: HEAVY HOG PRICES AT CHICAGO.