486 Creation hy Law. [Oct., 



not for many years been materially raised, although unlimited 

 ■wealth and energy are expended in the attempt. This is held 

 to prove that there are definite limits to variation in any special 

 direction, and that we have no reason to suppose that mere 

 time, and the selective process being carried on by natural law, 

 could make any material difference. But the writer does not 

 perceive that this argument fails to meet the real question, which 

 is, not whether indefinite and unlimited change in any or all 

 directions is possible, but whether such differences as do occur in 

 nature could have been produced by the accumulation of variations 

 by selection. In the matter of speed a limit of a definite kind as 

 regards land animals does exist in nature. All the swiftest animals 

 —deer, antelopes, hares, foxes, lions, leopards, horses, zebras, and 

 many others, have reached very nearly the same degree of speed. 

 Although the swiftest of each must have been for ages preserved, 

 and the slowest must have perished, "we have no reason to believe 

 there is any advance of speed. The possible limits under existing 

 conditions, and perhaps under possible terrestrial conditions, has 

 been long ago reached. In cases, however, where this limit had 

 not been so nearly reached as in the horse, we have been enabled to 

 make a more marked advance and to produce a greater difference of 

 form. The wild dog is an animal that hunts much in company, 

 and trusts more to endurance than to speed. Man has produced 

 the greyhound, which differs much more from the wolf or the 

 dingo than the racer does from the wild Arabian. 



Again, it is objected that the Pouter or the Fan-tail pigeon 

 cannot be further developed in the same direction. Variation seems 

 to have reached its limits in these birds. But so it has in nature. 

 The Fan-tail has not only more tail feathers than any of the three 

 hundred and forty existing species of pigeons, but more than 

 any of the eight thousand known species of birds. There is, of 

 course, some limit to the number of feathers of which a tail use- 

 ful for flight can consist, and in the Fan-tail we have probably 

 reached that limit. Many birds have the oesophagus or the skin 

 of the neck more or less dilatable, but in no known bird is it so 

 dilatable as in the Pouter pigeon. Here again the possible limit, 

 compatible with a healthy existence, has probably been reached. In 

 like manner the differences in the size and form of the beak in the 

 various breeds of the domestic Pigeon, is greater than that between 

 the extreme forms of beak in the various genera and subfamilies of 

 the whole Pigeon tribe. From these facts, and many others of the 

 same nature, we may fairly infer, that if rigid selection were 

 applied to any organ, we could in a comparatively short time 

 produce a much greater amount of change than that which occurs 

 between species and species in a state of nature, since the differences 

 which we do produce are often comparable with those which exist 



