Page:Popular Science Monthly Volume 19.djvu/431

Rh

part of the Academy's "Journal" contains four papers, of which the first two, embodying descriptions of the Miocene and Pleiocene fossils of the Caribbean area and Costa Rica, were written by the late William M. Gabb while in San Domingo, during the winter of 1877-'78, and have been published since his death. The third paper is on "The Terrestrial Mollusca inhabiting the Cook's or Harvey Islands," by Andrew Garrett. The next paper, on "The Placenta and Generative Apparatus of the Elephant," by Henry C. Chapman, M. D., is based on observations of a female elephant attached to a menagerie, that gave birth to a young one in Philadelphia in 1880, and establishes the interesting fact that the period of gestation of the elephant is from six hundred and thirty to six hundred and fifty-six days. The other papers are by Joseph Leidy, M. D., and are on "The Parasites of the Termites," and on the Bathygnatus borealis, a fossil saurian from Prince Edward Island.

present report embodies the conclusions that have been reached after careful examinations of the breeding-ground of the insects, of the regions in which they are permanently propagated, and of the "temporary region" where they may breed for a few years and then die out, with other knowledge that has been gained concerning their habits, and the best means of contending against them. The Commission claims that its prediction, that the series of invasions by the locust of the cultivated regions that began in 1874 would close in 1877, has been completely confirmed, and that its theory that the pest could not remain permanently in this region has been conclusively proved; consequently, the insect no longer excites the terror which its first appearances evoked. The locust is bred in the prairie tracts of the rainless district, in the loose, warm, gravelly soil, in the comparatively open spots, rather than in the thick grass, in different parts of a "permanent region," the area of which is not less than five hundred thousand square miles. The best single means of exterminating the broods would be to burn the grass while they are in the larva state; but this can not be relied on alone, because of the great extent of uninhabited country to which it would have to be applied, and because it can not be made thorough, since the burning would be lightest in the spots where the insects are thickest. The object must be promoted by other means, of which the first is to induce the settlement of the breeding district by farmers, who will fight the locusts in their homes; next, by the encouragement of irrigation, to bring unfriendly water to bear upon them, and of the planting of forests, in which they do not flourish; and by instituting a system of Signal-Service warnings of the progress of their migrations. The discussion of these points forms one of the most important chapters of the report; and this chapter, with the eight maps showing the vegetation of the regions the insects infest, has been also published separately. In addition to these topics, information is given concerning the migrations and ravages of locusts in other countries, their natural history and structure, and their natural enemies.

devotes a chapter to the description of each of the principal forms in which coöperation has been practiced with success. In the first chapter the workings of the Philadelphia building associations are explained in full; accounts are given of the English systems nearest like theirs; the English and American systems are compared; and cooperative banks are explained. The second chapter is devoted to the coöperative stores that have been established in Great Britain for the benefit of consumers; the third to those which are conducted in the interest of producers, of which the establishment of the Paisley shawl weavers is taken as the type. In the