Page:Popular Science Monthly Volume 29.djvu/735

Rh worrying cares which beset modern commercial and professional life, are as things that have never been." Another important advantage lies in the pure atmosphere and the long hours of uninterrupted sunshine and air that may be obtained, particularly in the warm latitudes, where the passengers may almost live on the deck. Other advantages lie in the equability of the climate, which varies but little from day to day, with freedom from chill, the saline particles in the air, the abundance of ozone, and the high average range of the barometer at sea. Drawbacks are not wanting, and they consist principally in the monotony of life on shipboard, the paucity of amusement and distraction, and the occasional discomforts of severe weather. The longer the voyage, provided it fall short of producing intolerable ennui, the greater the gain to health. Hence a sailing-vessel may be preferable to a steamer. A sailing-vessel has the further advantage that its progress being less rapid, the changes of climate in north and south voyages are more gradual than on the steamer. Sea-voyages are recommended to those who are suffering from affections of the respiratory organs, and to those who are simply overworked and in need of rest and change. But "those far advanced in disease, from whatever cause, and those threatened with melancholia or other form of insanity, should avoid a long sea-journey."

Fauna of Deep-lake Bottoms.—Although vegetation appears to be absent, the fauna of the depths of the Swiss lakes, considering as at great depths all points over seventy-five or eighty feet below the surface, is rich and abundant. All the deep-water classes except echinoderms are more or less perfectly represented, and, while the number of species is not very great, the types are remarkably varied. The individuals composing this fauna are generally of smaller size than those of corresponding littoral species; they are more opaque than in the pelagic fauna, and are seldom colored, for they live in a darker medium than the sea; and they are poor swimmers, and have no organs of attachment. Some of these animals exhibit curious features of adaptation, among the most remarkable of which is the smallness or entire absence of the eyes in some species. But this defect is far from being uniform. Thus, while some animals may be found with good eyes at the depth of one thousand feet, others will be found totally blind at one hundred feet, where there is still some light. This curious fact is explained by Dr. Plessis by supposing that an emigration has been going on from an extremely remote period and is still continuing, from the littoral and pelagic regions to the deep zone. The species which have most recently performed this emigration have not yet lost their eyes, while the species that went down in earlier times have had them atrophied, and have transmitted the defect to their offspring, even in regions where there is still light. This view is confirmed by the fact that we can find in the same species individuals wholly blind, others with their eyes in the way of atrophy, and others with sound eyes, but small, according as they may have descended from stocks that have emigrated at different epochs. Another feature in which adaptation is shown is in the organs of respiration. There are larvæ of Diptera in the lake-bottoms having a tracheal system, like those of surface insects, opening without by stigmata; but instead of air these tracheæ are filled with water. The Lymneæ of the bottom exhibit the same peculiarity. Forel always found their pulmonary sac filled with water. But they resume their normal method of respiration with a surprising facility as soon as they are placed in contact with the air, and this without appearing to suffer in the least.

School-Life and Chorea.—Dr. Octavius Sturgis, of the Westminster Hospital, London, has called attention to certain events and circumstances of school-life which during the year have within his own experience given origin to St. Vitus's dance. A patient whom he has had under treatment, a girl eleven years old, had been observed, before her chorea began, to be "restless at night, crying out in her sleep, or sitting up and rambling about her lessons. She was always eager to be at her books, and would bring home school-work to be prepared overnight. Owing, however, to the pressure of domestic matters, the lessons were often left