It is scarcely necessary to say that other classifications of social reform on its more hygienic side may be put forward. Thus W.H. Allen, looking more narrowly at the sanitary side of the matter, but without confining his consideration to the nineteenth century, finds that there are always seven stages: (1) that of racial tutelage, when sanitation becomes conscious and receives the sanction of law; (2) the introduction of sanitary comfort, well-paved streets, public sewers, extensive waterworks; (3) the period of commercial sanitation, when the mercantile classes insist upon such measures as quarantine and street-cleaning to check the immense ravages of epidemics; (4) the introduction of legislation against nuisances and the tendency to extend the definition of nuisance, which for Bracton, in the fourteenth century, meant an obstruction, and for Blackstone, in the eighteenth, included things otherwise obnoxious, such as offensive trades and foul watercourses; (5) the stage of precaution against the dangers incidental to the slums that are fostered by modern conditions of industry; (6) the stage of philanthropy, erecting hospitals, model tenements, schools, etc.; (7) the stage of socialistic sanitation, when the community as a whole actively seeks its own sanitary welfare, and devotes public funds to this end. (W.H.