A few years ago an experiment in the feeding of pigs was tried on the Cornell farm. Four groups of six pigs each were put in four different pens and fed four different rations. Though alike in breed and age; the groups began at once to differ in character. One group squealed more; another scratched more; another waxed fat faster. Every week they were weighed, and finally were butchered, hung up, and photographed. At that same time, at the Elmira Reformatory Mr. Brockway was experimenting on some criminals of the lower class. They were given daily baths, special physical exercises, and were fed on a specially bountiful diet. Scientific philanthropy stopped there, but photographs "before and after," reproduced in the printed reports, show the great physical improvement that resulted, and a marked change occurred likewise in disposition and intelligence. Many laboratory experiments have been made of late to test the chemical nature and the physiological effects of foods. It is becoming more fully recognized that the quality and quantity of food, and the cooking of it, have a great influence on the economic quality of the worker. [Sidenote: Clothing] The effect of the quality and amount of clothing, while of course varying with the climate, is in general of less practical importance. Loss of heat and energy, dulling the powers, stiffening the muscles, causing illness with many trains of evils, make ill-clad workmen inefficient. The cost of clothing enough for comfort is, however, comparatively small, the amount spent for ornament is comparatively high. Even more important in its effects on efficiency is housing. The conditions in the factory and in the home make for health or for disease. [Sidenote: Physical conditions surrounding labor grow worse or better] 4. _The growth of society is, for the average man, making some of the conditions of efficiency more difficult, others more easy, to secure._ In agricultural and sparse populations fresh air, sunshine, good water, and unbounded natural playgrounds for children, where they can grow into strong and efficient manhood, are free goods. As population grows more dense, these things become more difficult to secure; men are brought into unnatural conditions, the evils of slum and factory life develop, and the housing problem appears.