OCR Text |
Show ANNOTATIONS AND ADDITIONS. 301 sensible difference between America, India, and the West Coast of Africa. The distribution of organic beings over the surface of the earth does not depend wholly on thermic or climatic relations, which are of themselves very complicated, but also on geological causes almost unknown to us, belonging to the original state of the earth, and to cata trophes which have not affected all parts of our planet simultaneously. The large pachydermatous animals are at the present time wanting in the New Continent, while we still find them in analogous climates in Asia and Africa. These differences ought not to deter us from endeavoring to search out the concealed laws of nature, but should rather stimulate us to the study of them through all their intricacies. The numerical laws of the families of plants, the often striking agreement of the numbers expressing their ratios, where yet the species of which the families consist are for the most part different, conduct us into the mysterious obscurity which envelops all that is connected with the fixing of organic types in the species of plants and animals, or with their original formation or creation. I will take as examples two adjoining countries which have both been thoroughly explored-France and Germany. In France, many species of Grasses, Umbelliferre and Cruciferre, Compositre, Leguminosre, and Labiatre are wanting, which are common in Germany; and yet the numerical ratios of these six great families are almost identical in the two countries, as will be seen by the subjoined com-pari son. Fa.milies. Germany. France. Graminere. 1 1 3 n Umbelliferre. 1 ...L 22 21 Crueiferre. 1 1 11f IV Compositre. t ,1 Leguminosre. )1l f n Labiatre. ir; 1 2T This agreement in the number of species in each family compared to the whole number of phrenogamous species in the Floras of France and Germany, would not by any means exist if the German species which are missing in France were not replaced there by other types 26 |