Custom always exerts a great influence where there is question of choosing an avocation with the intention of devoting one's self to it entirely and exclusively. There is a public opinion which fixes the gradation of the different classes of labor and their appropriate reward, which is slow to change, and which both determines, and is determined by the relation of supply and demand. There is an equilibrium between the pleasantness of work and the rate of wages only in the case of such kinds of labor as are on the same social footing. It frequently happens, however, that the most repulsive work has to be performed by those who are forced to accept any pay and to be satisfied with it.[170-1] There are many branches of labor those engaged in which still form a kind of exclusive caste; and the pay of the higher branches is maintained at a high rate, especially by the fact that the members of the castes to which they belong are provident in their marriages. The lower classes are not in a condition to meet the preparation necessary to engage in such professions, even if they were certain of being afterwards reimbursed with interest for the outlay.[170-2] One of the chief causes of the lowness of wages paid to women is, that so few branches of labor are traditionally open to them, that the few that are, are intended to supply luxuries, and are, besides, for the most part, over-crowded. The distribution of the aggregate wages earned by any industry, among the higher and lower classes of workmen who coöperate in it, depends very largely on their social position relatively to one another.[170-3] [170-4] Here political forms and changes may exert the greatest influence.[170-5] Thus, the artificial increase of the wages of masters effected by the former guild-system was produced, to say the least, as much at the cost of the journeymen and apprentices as of the public. And if, on the other hand, it cannot be said that the most recent marked rise in wages, in so many countries, is merely the consequence of the extension of the parliamentary right of suffrage, certain it is that the two phenomena are very closely related, and that both are at once the effect and the cause of the intensified feeling of individuality and of the consciousness of constituting a class in the community of the lower strata of society.