Professor Cotta belongs to those who think the human race to be "the gradual perfection, through thousands of generations," of a lower order of creatures. "The human individual," he says, "even now, in the embryonic state, passes through the condition of various sorts of animals. The most eminent anatomists have shown that before birth we for a time resemble a polypal animal, then for a time a fish, next a reptile, till at last appear the characteristics of a mammalia. This is a fact which bears strongly in favor of our view. The genesis and development of the entire species seem to be here condensed in the growth of the individual." But while setting forth this peculiar view, Professor Cotta, with true German comprehensiveness, takes care to give a fair statement of opposing doctrines, and evinces nothing like a narrow dogmatism. The second volume, like the second volume of the Cosmos, is that which will most interest and delight the general reader. It contains thirty-two letters, mainly on the following subjects: the view of nature in general; the religious view; the various forms of the religious view; the aesthetic view; the inward connection of the aesthetic enjoyment of nature with its artistic representation; the scientific view as empirical science and natural philosophy; the relations of the various views of nature to each other; the poetic comprehension of nature among the Indians; the poetic comprehension of nature among the Jews, the Greeks, and the Romans; the Christian contemplation of nature; German poetry in the middle ages; Italian poetry; the poetic comprehension of nature in modern times; the representation of nature by painting, and its gradual appearance in the history of art; the physiognomy of plants in connection with the physiognomy of nature in general; description of several plant formations; general outlines of the animal world; history of the physical view of the universe; natural science among the Phenicians, the Greeks, at the time of the Ptolemies, at the time of the Roman Empire, and in the middle ages; natural history of modern times, Bacon, Copernicus, Kepler, Galileo, Newton; the mechanical doctrine of modern physics; the dynamic view of nature; Fichte's doctrine, and the natural philosophy of Schelling and Hegel. This volume, as will be easily understood, gives at once a history of religion, philosophy, art, literature, and science, in their relations to the outward universe. For instance, under the head of natural science among the Greeks, we have among other things an account of the doctrine of the Pythagoreans, Plato, and Aristotle; in treating the middle ages, Professor Schaller speaks of the Scholastics, Thomas Aquinas, Roger Bacon, Giordano Bruno, and Paracelsus. One of the most interesting parts of the whole is that on the poetic view of nature among the Hindoos, Jews, Greeks, Romans, Germans, and Italians, the historical statement being every where illustrated by copious quotations of admirable