Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1883 edition. Excerpt: ... CHAPTER XIL LAWS OP DEVELOPMENT OF ORGANIC TRIBES AND OF INDIVIDUALS. PHYLOGENY AND ONTOGENY. Uws of the Development of Mankind: Differentiation and Perfecting. --Mechanical Cause of these two Fundamental Laws.--Progress without Differentiation, and Differentiation without Progress.--Origin of Rudimentary Organs by Non-use and Discontinuance of Habit.-- Ontogenesis, or Individual Development of Organisms.--Its General Importance.--Ontogeny, or the Individual History of Development of Vertebrate Animals, including Man.--The Fructification of the Egg.-- Formation of the three Germ Layers.--History of the Development of the Central Nervous System, of the Extremities, of the Branchial Arches, and of the Tail of Vertebrate Animals.--Causal Connection and Parallelism of Ontogenesis and Phylogenesis, that is of the Development of Individuals and Tribes.--Causal Connection of the Parallelism of Phylogenesis and of Systematic Development.--Parallelism of the three Organic Series of Development. If man wishes to understand his position in nature, and to comprehend as natural facts his relations to the phenomena of the. world cognisable by him, it is absolutely necessary that he should compare human with extrahuman phenomena, and, above all, with animal phenomena. We have already seen that the exceedingly important physiological laws of Inheritance and Adaptation apply to the human organism in the same manner as to the animal and vegetable kingdoms, and in both cases interact with one another. Consequently, natural selection in the struggle PROGRESS AND DIFFERENTIATION. 281 for life acts so as to transform human society, just as it modifies animals and plants, and in both cases constantly produces new forms. The comparison of the phenomena of human...
