In the earlier judicial decisions sustaining the ten-hour laws for women the existence of this special danger and need was rather assumed than supported by evidence. The argument for the Oregon law before the Supreme Court of the United States for the first time laid all stress and emphasis upon the documentary testimony which had been accumulated in scientific treatises and official publications, showing the evil effects of overexertion and overfatigue upon women employed in the monotonous routine of mechanical labor. In marshaling medical, social and economic, instead of legal authorities, Mr. Brandeis, the counsel for the state of Oregon, clearly recognized that if the principle of freedom of contract is to be accepted as part of the constitution, the validity of the limitation of hours of labor becomes a question of fact, which must be answered upon the basis of observation and experience. The same line of argument was presented still more elaborately (and again by Mr. Brandeis) in the Illinois case. Attention was called to the extreme monotony of labor attending the minute subdivision of manufacturing processes, to the increasing strain of factory work due to the speeding of machinery, and to the general baneful effects, moral as well as physical, of overexertion and overfatigue. It is impossible to glance over the array of extracts from authoritative sources gathered from different countries without realizing that an entirely new light is thrown upon the subject of long hours in industry, with primary and specific reference to the work of women. A case for the exercise of the police power, even upon its most conservative basis, is made out such as had never before been presented when the validity of labor legislation was at issue. A showing of facts such as this might well induce a court to sanction state interference with the freedom of contract, while insisting to the fullest extent upon the same measure of constitutional right for women and men.