7<J REVERSION. [IXTROD. 



to interpret Homology on this view of Heredity, I have already 

 -poki-n in Section vi. 



- -.ndly, tin- metaphor of Heredity misrepresents the essential 

 phi-iioiin-non of reproduction. In the light of modern investiga- 

 tion-, an. I especially those of Weismann on the continuity of the 



in - -i-lls, it is likely that the relation of parent to offspring, 

 it it h;us any analogy with the succession of property, is ratln-r 

 thai of trustee than of testator. 



II' reafter, perhaps, it may be found possible to replace this 

 metaphor by some more correct expression, but for our 

 pr.--.-nt purpose this is not yet necessary. In the first exami- 

 nation of the facts of Variation, I believe it is best to 

 att'-nipt no particular consideration of the working of Heredity. 

 Tip- phenomena of Variation and the origin of a variety must 

 ii'-r,- ,-irily be studied first, while the question of the perpetua- 

 tion of i lie variety properly forms a distinct subject. Whenever 

 in tin- cases given, observations respecting inheritance are forth- 

 "miiig they will be of course mentioned. But speaking of dis- 

 coiii unions Variation in general, the recurrence of a variation 

 in offspring, either in the original form or in some modification 

 of it. has been seen in so many cases, that we snail not go far 

 \\i-ong j,, a t least assuming the possibility that it mat/ reappear 

 in tin- offspring. At the present moment, indeed, to this state- 

 in. -nt th.'iv is little to add. So long as systematic experiments 

 in bivi-ding are wanting, and so long as the attention of naturalists 

 i- limit. -d to the study of normal forms, in this part of biology 

 which is perhaps of greater theoretical and even practical im- 



mce than any other, there can be no progress. 



-) 



Reversion. 



Around 'lii 1 term Reversion a singular set of false ideas have 



gathered themselves. ()u the hypothesis that all perfection and 



completenes of i,,nu O r of eon-elation of parts is the work of 



ti"ii it is difficult to explain the discontinuous occurrence 



f..rm- ].o sing such perfection and completeness. To 



'"'' these, bhe hyp..ihe.sis of Reversion to an ancestral 



. proposed, and with some has found favour. That this 



tion is inadmissible is shewn at once by the frequent occur- 



ice U discontinuous Variation, of forms which though equally 



"'""I .-'II '" ancestral. In the case of Veronica and 



l"i- example, a host ,,f symmetrical forms of the floral 



may !,. seen occurring suddenly as sports, ;m <l O f these 



? b : " l > '""' '"''.v conceivably have been ancestral, the same 



supposed of all, for their forms are mutually exclusive. 



Veronica bwbatunii, for instance, are many symmetrical 



having two posterior petals, like those of other Scrophu- 



these may reasonably be supposed to be ancestral but 



