Page:Popular Science Monthly Volume 29.djvu/807

Rh genera are known, nearly half being marine, the rest fresh-water forms. The forms most familiar to us are Cambarus and Astacus. The latter is common on the Pacific slope and in Europe, while the former is the familiar form of our Eastern rivers and streams, finding their way into the Atlantic Ocean. In many localities their burrowing habits are productive of great damage; this is especially so in the levees of the Mississippi. In some parts of the South they are valued as food, and they can generally be found at Fulton Market, New York, a few people evidently knowing their delicacy in salads, etc. In Europe they have long been used as food, and so great is the demand for them in France that large farms are devoted entirely to their cultivation and breeding, the industry affording a profitable income. A study of the habits of these creatures will well repay the student, as many of them are very curious and interesting. They differ from many of the rest of the ten-footed crustaceans in not passing through the various larval stages that characterize the growth of so many of their allies.



HILE George Eliot was still a writer of essays, she complained that the "psychology of the lower classes" was misunderstood by nearly all who had to do with them, from legislators to novelists. She therefore said approvingly, in reviewing the works of W. H. Riehl, that he was "first of all a pedestrian, and only in the second place a political author." In literature, the work of portraying truly the lower classes has since been prosecuted with zeal by herself and others; but social science still shuns methodic observation.

The number of social facts is so nearly infinite that many have lacked the courage even to begin the work of collecting them. Frederic Le Play was a man who had the courage.

Not a few of the French economists and students of social science have received their early training in the polytechnic schools of Paris. The lesson which their early education seems usually to have taught them most thoroughly is that of the omnipotence of the human reason; they have too often attempted to reform the world by a dead-lift effort of the intellect. The lesson, however, which Le Play derived from his training in the School of Mines and applied to his work in the study of society was that of the vital importance of observation and analysis. His life in theory-breeding Paris only convinced him that social theorizing was the curse of the French people. In 1824 he came to the metropolis, being then in his eighteenth year, and as during his long life, which lasted till 1882, he watched the kaleidoscopic 