422 CONCLUDING EEMAEKS. Chap. XXVIII. 



What grand results have followed from the long-contiimed 

 action of methodical and unconscious seleQtion. regulated to a 

 certain extent by natural selection, we see on everj^ side of us. 

 Compare the many animals and jDlants which are displayed at 

 our exhibitions with their parent-forms when these are known, 

 or consult old historical records with respect to their former 

 state. Most of our domesticated animals have g-iven rise to 

 numerous and distinct races, but those which cannot be easilv 

 subjected to selection must be excepted — such as cats, the 

 cochineal insect, and the hive-bee. In accordance with what 

 we know of the process of selection, the formation of our 

 many races has been slow and gradual. The man who first 

 observed and preserved a pigeon with its oesophagus a little 

 enlarged, its beak a little longer, or its tail a little more 

 expanded than usual, never dreamed that he had made the 

 first step in the creation of a pouter, carrier, and fantail- 

 pigeon. Man can create not only anomalous breeds, but 

 others having their whole structure admirably co-ordinated 

 for certain purposes, such as the race-horse and dray-horse, or 

 the greyhound and bulldog. It is by no means necessary 

 that each small change of structure thronghout the body, 

 leading towards excellence, should simultaneously arise and 

 be selected. Although man seldom attends to diiferences in 

 organs which -are important under a physiological point of 

 view, vet he has so profoundly modified some breeds, that 

 asuredly, if found wild, they would be ranked as distinct 

 genera. 



The best proof of what selection has eifected is perhaps 

 aff"orded by the fact that whatever part or quality in any 

 animal, and more especially in any plant, is most valued by 

 man, that part or quality differs most in the several races. 

 This result is well seen by comparing the amount of difference 

 between the fruits produced by the several varieties of fruit- 

 trees, between the flowers of our flower-garden plants, between 

 the seeds, roots, or leaves of our culinary and agricultural 

 plants, in comparison with the other and not valued parts of 

 the same varieties. Striking evidence of a different kind is 

 afforded by the fact ascertained by Oswald Heer,^ namely, 

 that the seeds of a large number of plants, — wheat, barley, 



8 ' Die Pflanzon der Pfahlbauten,' 1865. 



