VARIATION. 75 



gone on selecting pouters for length of body, 

 and we have seen that their vertebrae are gen- 

 erally increased in number, and their ribs in 

 breadth. Tumblers have been selected for their 

 small bodies, and their ribs and primary wing- 

 feathers are generally lessened in numbe^. 

 Fantails have been selected for their large, 

 widely-expanded tails, with numerous tail 

 feathers, and the caudal vertebrae are increased 

 in size and number." Among cattle we find 

 that the hair and horns are correlated; so also 

 the color of the face and the extremities; and 

 some have thought that the circulatory system 

 has something more than a mere physiological 

 effect on the hide, being correlated with it; 

 the connection between color of the hide and 

 of the hair is well settled. An effort was 

 at one time made to show that the connec- 

 tion between the milk glands and the nutri- 

 tive organs were thus correlated. That- is, 

 that if the milk glands were largely developed 

 it would so affect the organs of nutrition as 

 to prevent the rapid accumulation of flesh. 

 Perhaps a more accurate statement of this 

 view would be that the milk glands and the 

 organs of flesh-production were in a three-fold 

 bond with the nutritive organs, which so acted 

 as to prevent a development of cattle in a high 

 degree as both milkers and beef-makers. The 

 correlation of course being something more 



