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22 



INHERITANCE. 



Chap. XII. 



coloured bird it does not answer to pair two jonquils, as the 

 colour then conies out too strong, or is even brown. So a^ain 

 if two crested canaries are paired, the young birds rarely inherit 

 this character : 57 for in crested birds a narrow space of bare skin 

 is left on the back of the head, where the feathers are up-turned 

 to form the crest, and, when both parents are thus characterised 

 the bareness becomes excessive, and the crest itself fails to be 

 developed. Mr. Hewitt, speaking of Laced Sebright Bantams, 



says 58 that, " why this should be so, I know not, but I am con- 

 fident that those that are best laced frequently produce offspring 

 very far from perfect in their markings, whilst those exhibited 

 by myself, which have so often proved successful, were bred 

 from the union of heavily-laced birds with those that were 

 scarcely sufficiently laced." 



It is a singular fact that, although several deaf-mutes often 

 occur in the same family, and though their cousins and other 

 relations are often in the same condition, yet their parents are 

 very rarely deaf-mutes. To give a single instance: not one 

 scholar out of 148, who were at the same time in the London 

 Institution, was the child of parents similarly afflicted. So again, 

 when a male or a female deaf-mute marries a sound person, their 

 children are most rarely affected : in Ireland out of 203 children 

 thus produced one alone was mute. Even when both parents 

 have been deaf-mutes, as in the case of forty-one marriages in 

 the United States and of six in Ireland, only two deaf and dumb 

 children were produced. Mr. Sedgwick, 59 in commenting on 

 this remarkable and fortunate failure in the power of trans- 

 mission in the direct line, remarks that it may possibly be 

 owing to " excess having reversed the action of some natural 

 law in development." But it is safer in the present state of our 

 knowledge to look at the whole case as simply unintelligible. 



With respect to the inheritance of structures mutilated by 



injuries or 



altered 



disease it is difficult to come to any 



57 Bechstein, ' Naturgesch. Deutsch- 

 lands,' b. iv. s. 462. Mr. Brent, a great 

 breeder of canaries,, informs me that 

 lie believes that these statements are 

 correct. 



58 'The Poultry Book,' by W. B. 



Tegetmeier, 1866, p. 245. 



59 ' British and Foreign Med.-Chirurg. 

 Eeview,' July, 1861, pp. 200-204. Mr. 

 Sedgwick has given such full details on 

 this subject, with ample references, that 

 I need refer to no other authorities. 







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