Outlines of Universal History, Designed as a Text-book and for Private Reading

by George Park Fisher

INSTRUMENTS IN MEDICINE AND SURGERY.—The microscope has rendered inestimable service to the healing art. Rare ingenuity has been exerted in contriving surgical instruments by which difficult operations are performed with comparative safety and without pain. In medicine and surgery, the discovery of anesthetics for the general or partial suspending of nervous sensibility is one of the triumphs of practical science in later times. Chloroform was brought into general use in the medical profession in 1847; although it had been discovered, and had been used by individuals in the profession, much earlier. Nitrous oxide was first used by Horace Wells, a dentist of Hartford, in the extraction of a tooth (1844). In 1846 the great discovery of anæsthetic ether, by Morton of Boston, was first applied in surgery. Jackson and others were claimants, with more or less justice, to a part in the honors of this discovery. Lately cocaine has been found to benumb the sensibility of the more delicate membranes, as those of the eye and the throat. In auscultation, or the ascertaining of the state of the internal organs by listening to their sound, a very valuable instrument is the stethoscope. The principle of the ophthalmoscope, that wonderful instrument for inspecting the interior of the eye, was expounded by Helmholtz in 1851. By its aid, not only the condition of that organ is explored, but indications of certain diseases in the brain, and in other parts of the body, are discovered. Helmholtz did an equal work in acoustics. The recent discovery and use of the X-rays has assisted surgeons in locating foreign substances and in diagnosing disease.

THE SPECTROSCOPE: PHOTOGRAPHY.—In connection with the phenomena of light, the spectroscope, by which the chemical elements entering in the composition of the sun and of other heavenly bodies are ascertained, is one of the marvels of the age. The way was paved for this discovery by a succession of chemists and opticians,—Fraunhofer (1814), Brewster (1832), Sir John Herschel (1822), J. W. Draper, and others; but the instrument was devised by Kirchhoff and Bunsen. Photography, or the art of making permanent sun-pictures, is the result of the labors of Niepce (who died in 1833), Daguerre (1839), Fox Talbot, an Englishman, J. W. Draper, and other men of science and practical artisans. Instantaneous photography has been of much service in the observation of eclipses and other astronomical phenomena. Progress has also been made in color-photography.

THE CONSERVATION OF ENERGY.—Perhaps the most important conclusion of physical science which has been reached in the recent period is the doctrine of the conservation of energy. Chemists had shown that the sum of matter always remains the same. In the transformations of chemistry no matter is destroyed, however it may change its form. Now, it has been proved that the quantity of power or energy is constant. If lost in one body, it reappears in another; if it ceases in one form, it is exerted in another, and this according to definite ratios. One form of energy is convertible into another: heat, light, electricity, magnetism, chemical action, are so related that one can be made to produce either of the others. This fact is termed the correlation of physical forces. Connected with the discovery of it are Meyer in Germany, and Grove and Joule in England. It has been expounded by Sir William Thompson, Helmholtz, Tait, Maxwell, etc. The truth was elucidated by Tyndall in his Heat considered as a Mode of Motion, and by Balfour Stewart in his Conservation of Energy. But Count Rumford, an American (1753-1814), the real founder of the Royal Institution, long ago opened the path for this discovery by furnishing the data for computing the mechanical equivalent of heat.

GEOLOGY AND PALEONTOLOGY.—In geology, from the publication of Lyell's work (1830), the tendency has more and more prevailed to explain the geological structure of the earth by the slow operation of forces now in action, rather than by violent convulsions and catastrophes. In 1831 Sedgwick and Murchison, likewise English geologists, commenced their labors. Agassiz published his Essay on the Glaciers in 1837, the precursor of like investigations by Tyndall and others. These are only a small fraction of the numerous body of explorers and writers in geological science. In the United States, Benjamin Silliman (1779-1864), an eminent scientific teacher, lent a strong stimulus to the progress of geology, as well as of chemistry. Even in the branch of paleontology, or the study of the fossil remains of extinct animals, it would be impracticable to give the names of those who have added so much to our knowledge of the earth and its inhabitants in the ages that preceded man.

ASTRONOMY.—The great French geometers, Lagrange and Laplace, made an epoch in astronomical science. Since their time, however, there has been a large increase of knowledge in this branch. The discovery of the planet Neptune (1846) by Galle, as the result of mathematical calculations of Leverrier, which were made independently also by Adams, was hailed as a signal proof of scientific progress; and, recently, the discovery of a fifth satellite of Jupiter. Besides Neptune hundreds of thousands of stars have been discovered and registered. Mathematical astronomy has advanced, while the study of nebulae and of meteors, and the investigation of the constitution of celestial bodies by the help of the spectroscope, are among the more recent achievements of this oldest of the sciences. Among the names identified with the recent progress of astronomy are Sir John Herschel and A. Herschel, Maxwell, Struve, Secchi, Bessel, Bond, Peirce, Newton, Newcomb, Young, Lockyer, Schiaparelli.

PROGRESS IN CHEMISTRY.—In chemistry the major part of the more rare elements have been discovered since the century began. It was proved in 1819 that the capacities for heat which belong to the atoms of the different elements are equal. In the same year Mitscherlich's law was propounded,—the law of isomorphism, according to which atoms of elements of the same class may replace each other in a compound without altering its crystalline structure. Chemists have directed their attention to the molecular structure—the ultimate constitution—of various compounds. Faraday (1791-1867) developed the relations of electricity to chemistry. Liebig (1803-1873), a German chemist, in connection with numerous laborers in the same field, made interesting contributions in the different departments of chemical science. Among the recent elements which have been discovered are argon, which enters into the composition of air, helium, and radium.

BIOLOGY.—No branch of natural science has been more zealously cultivated of late than biology. Among those who have given an impulse to the study of natural history, one of the most eminent names is that of Charles Darwin. His work on The Origin of Species (1859) advocated the opinion that the various species of animals, instead of being all separately created, spring by natural descent and slow variation from a few primitive forms of animal life. He laid much stress upon "natural selection," or the survival of the strongest or fittest in the struggle for existence. With the name of Darwin should be associated that of Wallace, who simultaneously propounded the same doctrine. The general doctrine of evolution, or of the origin of species by natural generation, has been held in other forms and modifications by Richard Owen, and other distinguished naturalists. One of the most noted opponents of the evolution doctrine in zoology was Louis Agassiz (1807-1873), a very able and enthusiastic student of nature. One of its most eminent expounders and defenders was Huxley. Some have sought to extend the theory of natural development over the field of inorganic as well as living things, and to trace all existences back to nebulous vapor.

ARCHEOLOGY.—Geology lends its aid to archeology, or the inquiry into the primitive condition of man. Not only has much light been thrown on obscure periods of history, by the uncovering of the remains of Babylon, Assyria, and other abodes of early civilization, and by the deciphering of monumental inscriptions in characters long forgotten; but the discovery of buried relics of prehistoric men has afforded glimpses of human life as it was prior to all written memorials. One of the most instructive writers on this last subject is Tylor in his Primitive Culture, and in other works on the same general theme.

PHILOSOPHY AND LITERATURE.

PHILOSOPHY IN FRANCE.—Victor Cousin (1792—1867), a brilliant thinker and eloquent lecturer and writer, founded in France the eclectic school of philosophy. He aimed to construct a positive view on the basis of previous systems, which he classified under four heads,—idealism, sensualism, skepticism, and mysticism. In his teaching, he sought a middle path between the German and the Scottish schools, leaning now more decidedly to the one, and now to the other. Jouffroy (1796-1842), the most prominent of Cousin's disciples, but more exact and methodical than his master, wrote instructively, especially on aesthetics and moral philosophy. Philosophy in France took an altogether different direction in the hands of Auguste Comte (1798-1857), the founder of the positivist school. He taught that we know only phenomena, or things as manifested to our consciousness, and know nothing either of first causes, efficient causes, or of final causes (or design). We are limited to the ascertaining of facts by observation and experiment, which we register according to their likeness or unlikeness, and their chronological relation, or the order of their occurrence in time.