

36 



INHERITANCE. 



Chap. XIII 



The law of reversion is equally powerful with hybrids, when 

 they are sufficiently fertile to breed together, or when they 

 are repeatedly crossed with either pure parent-form, as with 



g 



It is not necessary to g 



for in the 



case of plants almost every one who has worked on this subject 

 from the time of Kolreuter to the present day has insisted on this 

 tendency. Gartner has recorded some good instances ; but no 



has g 



more striking cases th 



Naudin 



The 



dency differs in deg 

 partly depends, as w 



or strength 



in different groups, and 



shall presently 



the fact of 



parent-plants having been long cultivated. Although the 

 dency to reversion is extremely general with nearly all mon 

 and hybrids, 



ids, it cannot be considered as 

 of them : there is, also, reason to b 



o 



ariablv charac- 



be mastered by long-continued selection ; but these subjei 

 will more properly be discussed in a future chapter on Crossh 

 From what we see of the power and scope of reversion, both in 

 pure races and when varieties or species are crossed, we may- 

 infer that characters of almost every kind are capable of reap- 

 pearance after having been lost for a great length of time. But 



m 



it does not follow from this that in each particular case certain 

 characters will reappear : for instance, this will not occur when a 

 race is crossed, with another endowed with prepotency of trans- 

 ssion. In some few cases the power of reversion wholly fails, 

 without our being able to assign any cause for the failure : thus it 

 has been stated that in a French family in which 85 out of above 

 600 members, during six generations, had been subject to night- 

 blindness, " there has not been a single example of this affection 



the children of parents who were themselves free from 



"19 



Reversion through Bud-propagation — Partial Reversion, hy seg- 



ments in th 



ft 



fruit, or in different parts of the 



w Kolreuter gives cases in his ' Dritte p. 485. Dr. H. Dobell, in ' Med.- 



Fortsetzung,' 1766, s. 53, 59 ; and in his Chirurg. Transactions/ vol. xlvi., gives 



well-known ' Memoirs on Lavatera and an analogous case, in which, in a large 



Jalapa.' Gartner, ' Bastarderzeugung,' family, fingers with thickened joints 



437, 441, &c. Naudin, in his were transmitted to several members 



Eecherches sur THybridite, Nouvelles during five generations; but when the 



Archives du Museum,' torn. i. p. 25. blemish once disappeared it never re- 

 appeared. 



s. 



Sedgwick 



m 



19 Quoted by Mr. 

 c Med.-Chirurg. Keview/ April, 1861. 



fn 

 a 



P£ 



foi 



pa] 



to 



