472 INHEEITANGE. Chap. XII. 



departing from tlie parental type in many characters.^* 

 Metzger, as stated in the ninth chapter, found that certain 

 kinds of wheat brought from Spain and cultivated in 

 Germany, failed during many years to reproduce themselves 

 truly ; but at last, when accustomed to their new conditions, 

 they ceased to be variable, — that is, they became amenable 

 to the power of inheritance. Kearly all the plants which 

 cannot be propagated with any approach to certainty by seed, 

 ai'e kinds which have been long propagated by buds, cuttings, 

 oiisets, tubers, &c., and have in consequence been freqiiently 

 exposed during what may be called their individual lives to 

 widely diversified conditions of life. Plants thus propagated 

 become so variable, that they are subject, as we have seen in 

 the last chapter, even to bud-variation. Our domesticated 

 animals, on the other hand, are not commonly expos^ed during 

 the life of the individual to such extremely diversified con- 

 ditions, and are not liable to such extreme variability ; there- 

 fore they do not lose the power of transmitting most of their 

 characteristic features. In. the foregoing remarks on non- 

 inheritance, crossed breeds are of course excluded, as their 

 diversity mainly depends on the unequal development of 

 character derived from either parent or their ancestors. 



Conclusio7i. 



It has been shown in the early part of this chapter how com-' 

 monly new characters of the most diversified nature, whether 

 normal or abnormal, injurious or beneficial, whether aflecting 

 organs of the highest or most trifling importance, are in- 

 herited. It is often sufiBcient for the inheritance of some 

 peculiar character, that one parent alone should possess it, as 

 in most cases in which the rarer anomalies have been trans- 

 mitted. But the power of transmission is extremely variable. 

 In a number of individuals descended from the same parents, 

 and treated in the same manner, some display this power in 

 a perfect manner, and in some it is quite deficient ; alid for 

 this difference no reason can be assigned. The effects of 

 injuries or mutilations are occasionally inherited; and we 



«3 Downing, ' Fruits of America,' p. 5 : Sageret, ' Pom. Phys.,' pp. 43, 72. 



