for great improvements in the health of the wage classes by the construction of improved dwellings; but, he confessed, in many cases workmen required to be taught to attend to precautions devised for their health. On the subject of sickness caused by insanitary conditions, he quoted the remark of an East London clergyman that the "poor go on living in wretched places, but have much ill-health." He showed from Mr. Burdett's figures that the London voluntary hospitals and dispensaries cost nearly £600,000 a year to administer--an expenditure incurred mainly for the purpose of "patching up" the wretched poor who had been injured by bad drainage, want of ventilation and the like; and he urged that it might be safely assumed preventive measures would bring down the death-rate of the wage class to one-half, reducing also the sickness rate in at least a similar proportion. By means of this item alone the wage-earning power of the industrious classes would be enlarged by some millions of pounds, and their comfort correspondingly increased. There would also, he contended, be other distinct economies, for there would be less need for much of the accommodation in prisons, reformatories, and workhouses now needed from evils incident to unhealthy circumstances and crowded dwellings. He dwelt upon the economic advantages of sanitary measures generally, dealing first with the subject of the conversion of sewage into manure, and then, in relation to the provision of healthful dwellings, such as those of the Metropolitan Association for Improving the Dwellings of the Industrial Classes, he showed that the cost of such dwellings had been about £1,900,000 for 11,000 persons. By the saving in life and health, through the continuance in earning power of men, whose lives would otherwise have been cut short, he estimated that the expenditure of the £1,900,000 for the 11,000 persons, by the addition often years' earning power to the heads of families, brought in a return of £4,600,000, and urged these facts as showing the pecuniary advantages accruing to the nation from sanitary improvements which led to decreased death and sickness rates. On the one hand, he said, insanitary dwellings and insanitary conditions of life engendered sickness, entailed poverty, and fostered crime, while improved dwellings insured improved health, and by affording a security for the more continuous earning of wages created the possibility of a comfortable home. Advanced sanitarians had long preached these doctrines, and he was happy to think that they were at last beginning to hear some results, and in those results he saw the means of developing morality, contentment, and happiness among the people. * * * * * [NATURE.] PSYCHOLOGICAL DEVELOPMENT IN CHILDREN.