368 Appendix B 



that affected the shape of the hands and feet. These would 

 not be produced as the result of the use of the organs or as 

 acquired variations, but simply from variations in the germ 

 plasm. There might be thousands of other variations in other 

 parts of the body in the meantime. The miscellaneous varia- 

 tions, however, would not persist. But as soon as variations 

 appeared which affected the shape of the hands and the feet, 

 the fact that the animal had continued to climb trees would 

 make these variations of value, and therefore subject to natural 

 selection. Selection would follow, and thus in time the monkeys 

 might be expected to inherit hands and feet well adapted for 

 climbing. The acquired variations, in such a case, had nothing 

 to do with producing the changes directly, but they did shield 

 the animal from destruction until congenital variations appeared. 

 Acquired variations have determined that the individuals shall 

 live in trees, and this life has determined what congenital 

 variations will be preserved. Indirectly, therefore, the acquired 

 variations guide evolution. 



" This factor would also aid in explaining the origin of co- 

 ordinated structures, which have been always a puzzle to natural 

 selection. How, for example, can we imagine that chance con- 

 genital variations shall at the same time cause an increase in the 

 size of the deer's horns and in the strength of his neck and 

 shoulders ? Either without the other could not exist. But we 

 can imagine that some congenital variation increased the size of 

 the antlers, and then clearly enough acquired characters would 

 of necessity increase the size of the neck and shoulder muscles, 

 thus enabling the animal to carry the large antlers. This 

 might continue many generations. Eventually another series of 

 variations of a congenital character might affect these muscles. 

 These would be at once selected, if they enable the animal to 

 carry its antlers more easily, and thus in time neck and antlers 

 would be coordinated to each other. The animal by acquired 

 characters adapts itself to its conditions and waits until a proper 

 congenital character appears. A combination of characters to 

 make a coordinated system of organs is thus made possible, in 

 a manner that natural selection alone is unable to account for." 



