THE POPULAR SCIENCE MONTHLY.
human system from without, and mostly through the inbreathed air, the author advocates the charging the mouth and nostrils with antiseptic substances so as to render the breath and the tissues more immediately exposed unfriendly to the development of the contagium. When the floating infective particle presents itself either for local manifestation or for absorption, it may require "but slight unfriendliness of reception to prevent morbid result." In diseases like diphtheria and scarlet fever, which at the outset have such marked local manifestation as to lead us to believe that they are local before they are constitutional, topical application of remedies seems to be clearly indicated. But the author thinks that the introduction of certain substances into the blood is a still more effectual mode of combating contagia. In this way not only are the portals of entrance protected, but the fluids, glands, etc., of the system are so permeated with the antiseptic or antifermentative agent as to be able to withstand the action of the disease-germ. How much may be due to the local hinderance to fertilization, and how much to the constitutional resistance established, may not in each case be easy to determine. But when we consider how readily chlorate of potassium, after being administered, is found in the secretions, how soon a few grains of pure protochloride of iron increase the number of the red globules of the blood, how defibrination of the blood is retarded by certain agents, we are justified in the hope that our power to suspend the action of disease-poisons will yet be greatly augmented.
Creosote as a Timber-Preserver.—Railway-ties, dried, and saturated with creosote, will last, according to Mr. E. R. Andrews, for twenty years or more in good condition. In ties so treated the spikes intended to hold the rail do not corrode nor work loose. Then, too, the surface of the tie under the rail does not decay nor wear, because it is not affected by alternate dryness and moisture. In the construction of wharves and in ship-building, creosoted timber is also of great advantage. It is proof against the ravages of the Teredo navalis and other mollusks which cause such destruction of timbers submerged in sea-water. The woods best adapted for the creosoting process are those which are light and porous, as these most readily absorb the creosote; so treated they become more solid and enduring than the most costly species of timber. "The cottonwood of the Southwest," writes Mr. Andrews, in the American Gaslight Journal, "can be made as useful as oak for ties. White pine absorbs creosote like a sponge, and the yellow pine of the South takes it readily also. In Englandfrom the Baltic is used altogether for ties, and I do not see why the despised fir from our forests may not be used for the same purpose here. Hemlock is good also; spruce is a firm, compact wood, and absorbs oil with more difficulty; neither does it require so much to preserve it. Oak has a coarse fibre, and is easily treated."
The Eyes of Deep-Sea Animals.—In giving to the National Academy of Sciences an account of recent dredging and sounding in the Gulf of Mexico, Prof. Alexander Agassiz referred to the question of sight in marine animals living at great depths. He said that the crustaceans and fishes taken from depths of from 1,500 to 1,900 fathoms or more present conditions diametrically opposite to one another with respect to vision, some of these creatures being eyeless or nearly so, others having eyes enormously developed, as if to enable them to see with the faintest glimmer of light. In the former class many very curious modifications of structure are to be seen taking the place of the eyes. The existence of these very wide differences of structure under identical conditions he regarded as strange, but, in the discussion which followed the reading of the paper, Profs. Cope and Gill held that this difference was precisely what we might expect, according to the evolution hypothesis. There is nothing surprising in the fact that in one set of animals "survival of the fittest" should work obliteration, and in another class abnormal development of the visual organs.
Studies of Embryo Life.—On opening the shell of a hen's-egg in the third day of incubation, Harvey noticed the heartbeats of the embryo, which, however, soon ceased. He then placed the egg in warm water, and the heart commenced to beat again. The same experiment, but with im-