I. THE REJECTION OF SELECTION.
Many years ago Semper[[25]] denied the power of selection to create an organ, declaring that the organ must have previously existed before selection could have increased and developed it. More recently Wolff[[26]] has distinguished himself by the vigor with which he has attacked the "task" of "setting aside the dogma of selection." Henry B. Orr[[27]] is also of opinion that selection is not the real cause of improved organic states; he regards it as a factor checking growth in certain directions, but not as a cause producing growth. Likewise Yves Delâge,[[28]] in his recent voluminous but in many respects excellent work, regards natural selection solely as a subordinate principle which is devoid of all power to create species (p. 391), although he grants to it certain functions, and even characterises it
as "an admirable and perfectly legitimate principle" (p. 371). A more pronounced opponent of selection, of any kind, as a principle creating species, is the Rev. Mr. Henslow,[[29]] whose views we shall discuss later, in Division VII. of this Appendix.
Finally, must be mentioned the name of Th. Eimer, as that of a pronounced and bitter enemy of the theory of selection. I shall leave it to others to decide whether he can properly be called an "opponent" of the principle, in the scientific acceptance of the word. I can see in the blind railings of the Tübingen Professor nothing but a reiteration of the same unproved assertions, mingled with loud praises of his own doughty performances and captious onslaughts on every one who does not value them as highly as their originator.[[30]]
The lack of confidence latterly placed in the theory of selection even by professed adherents of the doctrine, is well shown by such remarks as the following
from Emery,[[31]] who says: "Some pupils of Darwin have gone beyond their master and discovered in natural selection the sole and universal factor controlling variations. Thus there has arisen in the natural course of things a reaction, especially on the part of those who, while they accept evolution, will have naught to do with natural selection or Darwinism as they call it." Emery then professes himself a Darwinian, although not in the sense of Wallace and "other co-workers and pupils of Darwin." For him "natural selection is a very important factor in evolution, and in determining the direction of variation plays the highest part; but it is far from being the only factor and is probably also not the most efficient factor." Not the most efficient factor but plays the highest part!
II. CHEMICAL SELECTION.
If we refer adaptation to selection, we have also to trace back to this source the origin of the organic combinations which make up the various tissues of the body and which go by the collective name of muscular, nervous, glandular substance, etc. Lloyd Morgan has prettily likened the vital processes to the periodic formation and discharge of explosive substances.[[32]] Unstable combinations are upon the application of a