the views of Darwin and Haeckel conclusions to which they certainly do not lead. But in the majority of cases, his work is full of real convincing power, and with the breadth of its philosophical view and with the sharpness of its definitions, as well as with its abundance of philosophic and especially botanical teachings and their ingenious application, it is directly destructive to the use of the selection theory as the principal key to the solution of the problems. Eduard von Hartmann describes the work in his publication, "Wahrheit und Irrthum im Darwinismus," ("Truth and Error in Darwinism"), as a mile-stone which marks the limits where Darwinism as such passed the summit of its influence in Germany. * * * * * {61} CHAPTER III. PRESENT STATE OF THE DARWINIAN THEORIES. Sec. 1. _The Theory of Descent._ The historical retrospect of the Darwinian theories, from their purely scientific side, leads us of itself to a critical review of their present state. We can briefly indicate in advance the result to which it will lead us, viz.: that the descent theory has gained, the selection theory has lost ground, the theory of development oscillates between both; but that all three theories have not yet passed beyond the rank of hypotheses, although they have very unequal hypothetical value. We can best arrange our review by beginning with that theory which is the most common, and which perhaps may still have value when both the others find their value diminished or lost: _the theory of descent_. From that we proceed to the _theory of evolution_, and from this to that of _selection_.