236 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 



From the first growth of the tree, many a limb and branch has decayed 

 and dropped off; and these fallen branches of various sizes may repre- 

 sent those whole orders, families, and genera which have now no living 

 representatives, and which are known to us only hi a fossil state. As 

 we here and there see a thin straggling branch springing from a fork 

 low down hi a tree, and which by some chance has been favored and is 

 still alive on its summit, so we occasionally see an animal like the 

 Ornithorhynchus or Lepidosiren, which in some small degree connects 

 by its affinities two large branches of life, and which has apparently 

 been saved from fatal competition by having inhabited a protected 

 station. As buds give rise by growth to fresh buds, and these, if 

 vigorous, branch out and overtop on all sides many a feebler branch, 

 so by generation I believe it has been with the great Tree of Life, which 

 fills with its dead and broken branches the crust of the earth, and 

 covers the surface with its ever-branching and beautiful ramifications. 



DIFFICULTIES AND OBJECTIONS TO NATURAL SELECTION AS 

 SEEN BY DARWIN 



Long before the reader has arrived at this part of my work, a crowd 

 of difficulties will have occurred to him. Some of them are so serious 

 that to this day I can hardly reflect on them without being in some 

 degree staggered; but, to the best of my judgment, the greater number 

 are only apparent, and those that are real are not, I think, fatal to the 

 theory. 



These difficulties and objections may be classed under the follow- 

 ing heads: First, why, if species have descended from other species 

 by fine gradations, do we not everywhere see innumerable, transitional 

 forms? Why is not all nature in confusion, instead of the species 

 being, as we see them, well defined ? 



Secondly, is it possible that an animal having, for instance, the 

 structure and habits of a bat, could have been formed by the modifica- 

 tion of some other animal with widely different habits and structure ? 

 Can we believe that natural selection could produce, on the one hand, 

 an organ of trifling importance, such as the tail of a giraffe, which 

 serves as a fly-flapper, and, on the other hand, an organ so wonderful 

 as the eye ? 



Thirdly, can instincts be acquired and modified through natural 

 selection ? What shall we say to the instinct which leads the bee to 

 make cells, and which has practically anticipated the discoveries of 

 profound mathematicians ? 



