Dollo's law of the non-reversibility of the phyletic development applies to reduced and missing organs as well as to functioning ones which have adapted their shapes to new conditions of living. Such an organ will never again regain its old structure, not even if the old conditions should return. Numerous instances show that this law only applies in general; exceptions prove that it does not apply absolutely, so that it is not really a law, but a rule. The larvae and (...) pupae of Chironomidae live, with relatively few exceptions, in water. Terrestrial species of the Chironomidae are undoubtedly descended from the aquatic. Of the Orthocladiinae-genusPseudosmittia, only species of which the larvae live on the earth were known up to now; the larva of the new speciesPseudosmittia Ruttneri has secondarily reverted to aquatic life. In them a number of their ancestors' adaptations have, it is true, remained intact; two such characteristics, however, have again taken the shape characteristic of aquatic life. So here we have a return to the original phylogenetic stage, as a result of the return of the original conditions of life. The specific pupal organs of the Trichoptera, adaptations to aquatic life, have completely disappeared in the purely terrestrialEnoicyla pusilla, they have partly disappeared in the semi-terrestrial original Trichopterae from the genusBeraea andCrunoecia. So here, too, we have a return to an original phylogenetic condition. In both cases ”réversibilité de l'évolution”.La thèse deDollo de la non-réversibilité de l'évolution phylogénétique se rapporte aussi bien aux organes réduits ou disparus, qu'aux organes en fonction, qui, dans de nouvelles conditions de vie ont changé leur forme; même au retour des anciennes conditions, un tel organe ne pourrait plus jamais obtenir sa structure originale. De nombreux exemples montrent que cette thèse il est vrai, est valable d'une façon générale; qu'elle n'est cependant pas absolue, donc qu'elle n'est point une loi, mais seulement une règle est prouvé par des exceptions. Ici nous montrons deux nouveaux exemples de ces exceptions: Les larves et les nymphes chironomides vivent dans l'eau, sauf des exceptions relativement peu nombreuses. Des espèces terrestres parmi les chironomides dérivent, sans aucun doute, de formes aquatiques. Du genre orthocladiinePseudosmittia, on ne connaissait jusqu'à présent que des espèces de larves vivant dans la terre; la larve de la nouvelle espècePseudosmittia Ruttneri a passé secondairement à la vie aquatique. Là, il est vrai qu'un nombre d'adaptations de forme de ces ancêtres à la vie terrestre se sont maintenues; deux de ces marques cependant, ont recouvré l'empreinte caractéristique de la vie aquatique. Ainsi retour à l'ancien stade phylogénétique quand reviennent les conditions de vie originales. Les organes spécifiques des nymphes des trichoptères, des adaptations à la vie aquatique, ont complètement disparu chezEnoicyla pusilla, qui est uniquement terrestre. Chez les trichoptères de source des genresBeraea etCrunoecia qui sont miterrestres, ils ont disparu en partie. Donc, il y a ici aussi un retour à une ancienne situation phylogénétique. Dans les deux cas: Réversibilité de l'évolution. (shrink)

A keen student of theology, August Friedrich Gfrörer became professor of history at the University of Freiburg and also sat as a representative in the Frankfurt parliament, agitating for the reunification of Protestantism and Catholicism. His academic work marked the modern period in the Christian study of Judaism, making full use of primary sources without pursuing an obvious apologetic or polemical agenda. This two-volume work, published in 1831, is a critical study of early Christianity and the influence that Judaism had (...) on the New Testament. Volume 1 provides a thorough exposition of Philo of Alexandria's philosophy and theology. Gfrörer also offers a biographical sketch of Philo and gives an informative overview of his writings and his time. (shrink)

A keen student of theology, August Friedrich Gfrörer became professor of history at the University of Freiburg and also sat as a representative in the Frankfurt parliament, agitating for the reunification of Protestantism and Catholicism. His academic work marked the modern period in the Christian study of Judaism, making full use of primary sources without pursuing an obvious apologetic or polemical agenda. This two-volume work, published in 1831, is a critical study of early Christianity and the influence that Judaism had (...) on the New Testament. Volume 2 is devoted to substantiating the thesis that the core principles of Philo's theology were already discernible among the Alexandrian Jews. Gfrörer traces how Philo's theology and philosophy were transplanted to Palestine via such sects as the Therapeutae and the Essenes as well as through the historian Josephus. The Apocrypha serve as Gfrörer's main primary source. (shrink)

A keen student of theology, August Friedrich Gfrörer became professor of history at the University of Freiburg and also sat as a representative in the Frankfurt parliament, agitating for the reunification of Protestantism and Catholicism. His academic work marked the modern period in the Christian study of Judaism, making full use of primary sources without pursuing an obvious apologetic or polemical agenda. This two-volume work, published in 1831, is a critical study of early Christianity and the influence that Judaism had (...) on the New Testament. Volume 1 provides a thorough exposition of Philo of Alexandria's philosophy and theology. Gfrörer also offers a biographical sketch of Philo and gives an informative overview of his writings and his time. (shrink)

Oswald Spengler (1880 - 1936) war ein deutscher Geschichtsphilosoph und Kulturhistoriker. Das hier vorliegende Werk August Messers über Spengler erscheint nur wenige Jahre nachdem Spengler mit seiner Zyklentheorie, die sich gegen eine lineare Geschichtsschreibung ausspricht, an die Öffentlichkeit getreten ist. Messer reflektiert diese und spürt den philosophischen Grundanschauungen Spenglers in ihrem innersten Zusammenhange nach. Auf diese Weise gelingt es Messer, ein sensibles und differenziertes Bild Oswald Spenglers und seiner Ideenwelt zu zeichnen. Sorgfältig bearbeiteter Nachdruck der Originalausgabe von 1924.