354 ACTION OF NATURAL SELECTION 



peared in the ducklings' wings. They increased also 

 in size of body; their legs became less fine, and they 

 lost their elegant carriage. Fresh eggs were then pro- 

 cured from wild birds, but the same result followed." 

 Again, Darwin* records that " according to Pallas, 

 and more recently according to Erman, the fat-tailed 

 Jirghisian sheep, when bred for a few generations in 

 Russia, degenerate, and the mass of fat dwindles away, 

 the scanty and bitter herbage of the steppes seems so 

 essential to their development." The fleece of sheep 

 imported from Europe to the West Indies is much af- 

 fected, and " after the third generation, the wool dis- 

 appears from the whole body, except over the loins; 

 and the animal then appears like a goat with a dirty 

 door-mat on its back. A similar change is said to take 

 place on the West Coast of Africa." Another in- 

 stance of the effect of climate on sheep is recorded by 

 Brewer.f Sheep taken from southeastern Ohio, a dis- 

 trict noted for its excellent wool, and pastured on the 

 alkaline soil of a certain portion of Texas, had the 

 texture of their wool much altered, and its reaction to 

 dyes showed obvious differences. Brewer states that 

 " the change in the character of the wool begins imme- 

 diately, but is more marked in the succeeding fleeces 

 than in the first. It is also alleged that the harshness 

 increases with succeeding generations, and that the 

 flocks which have inhabited such regions several gener- 

 ations produce naturally a harsher wool than did their 

 ancestors, or do the newcomers." 



The deteriorating effect of an Indian climate on 



*Ibid.,i. p. 102. 



t Vide Cope's " Factors of Organic Evolution," p. 435. 



