organic substances, such as alcohol, various kinds of ether, grape sugar, organic acids, fats, alkaloids, vegetable oils or perfumes, etc., are being manufactured in a purely chemical way, and the hope is well founded that in course of time we may also succeed in preparing directly from the elements sugars and albumins—yea, even the protoplasm or that organic primal substance out of which all living beings are evolving. What chemistry even now is capable of achieving is shown by the preparations made from coal tar of practicable pigments, perfumes, saccharines, and drugs.
Finally, we must mention in this place the discovery of argon, a hitherto unknown element of the atmospheric air, as well as the successful preparation of acetylene by Professor Moisson. This is a luminous gas which is sixteen times stronger than common gas, and has five times the illuminating power of Auer's gaslight.
Geology.—As we owe to the progress in chemistry the refutation of the theory of a vital principle, geology in like manner has disproved, chiefly through the labors of the gifted English geologist Lyell (1830-'33), the formerly accepted theory of great physical catastrophes or terrestrial revolutions and of separate acts of creation, and has shown that the past of the history of our globe (which in its evolutionary process advances slowly but continuously) is nothing but its unrolled present.
Paleontology.—In close connection with geology is paleontology, or the knowledge of the former life of our globe. This has been raised to the rank of a science only during the present century. Now this science has so far advanced that we can survey the gradual development of the entire organic world, and find that those transitional and intermediate forms required of the evolutionary theory are no longer missing. The vast North American plains are especially remarkable as having been found to be rich treasure houses of such forms.
Anatomy.—Closely connected with paleontology are anatomy and the discovery made in this science of the cell as the primordial element or fundamental form of the whole organic world. This discovery was made by Schwann and Schleiden in 1839, after the microscope had been brought, through the efforts of Amici, to such a perfection as to make possible by its use the more and more subtle investigation of animal tissue. Through the discovery of the cell, the unity, as to kind and origin, of everything living was demonstrated; and it was shown that even the highest and most complicated organisms were simply combinations of cells in a more or less changed condition. Then, in 1859, Virchow made an ingenious application of the cell theory to medical science. Virchow, in his Cellular-Pathologie, searched in the modified cell for the nature
