The economic necessity for law precedes the legal expression. The need for a statute is felt long before it is formulated. This is readily recognized by political economists and lawyers. Judge Dicey, in his book entitled, "Law and opinion in England," (Lond. 1905, p. 367) says: "A statute * * * is apt to reproduce the public opinion, not so much of today as of yesterday." Since a legislative reference library is busied with the process of law-making, rather than with the administration or interpretation of law, the trend will be toward the economic headings rather than the legal. The tendency of law is to crystallize, and subjects legal in aspect are likely to be complete in themselves, and therefore less amenable to library purposes. As an example, a subject heading such as "Eminent domain" is legal in its nature. This will be used in the main body of the catalog without a doubt. It may have cross references of both a legal and an economic nature. At the same time "Eminent domain" may be used as a subdivision of economic headings, such as "Railroads," "Street railways," "Telegraphs," and "Telephones." This shows how the legal aspect of an economic question may be brought directly in touch with the economic phase of the question. Another example is "Liquor problem;" as it is used in the subject headings, it is an economic question, yet we use the subdivision "Illegal traffic" which includes purely a legal phase. "Discrimination," a legal term, will cross refer to some specific form under an economic heading such as "Railroads--Rebates." It is often necessary to refer from some rather popular headings to legal forms, such as "Funeral expenses, see Estates of deceased persons." Again it may be necessary to mix the two with a heading such as "Ethics--Business and professional," with cross references from legal headings, such as "Professional ethics," "Legal ethics," "Medical ethics," etc. The general conclusion reached is that there is likely to be either subdivisions or cross references back and forth from any type of heading to any other type, with one exception, namely, an economic subdivision of a legal heading. In our experience in Wisconsin, we have not found this combination of headings either necessary or advantageous. This fact but emphasizes what has already been said, that law once established, becomes permanent and fixed in character. Geographical divisions as main headings should be used sparingly, but geographical subdivisions of subjects are very helpful. Primary election laws, road laws, tax laws, will all be more available if divided by states, not only in the classification, but in the subject heading. If clearness or rapidity of service demand subdivisions, they should be made, even though there be few cards under each subdivision. Many helpful suggestions for subject headings and cross references may be obtained from law indexes, law encyclopedias, and the New York index of legislation.