SOME MISUNDERSTANDINGS CONSIDERED i8i 



Misunderstanding III — Begging the question by starting 

 with what is not proved to he a modification. — There is no rele- 

 vancy in citing cases where an abnormal bodily peculiarity 

 re-appears generation after generation, unless it be shown that 

 the peculiarity is a modification, and not an inborn variation 

 whose transmissibility is admitted by all. Short-sightedness 

 may recur in a family-series generation after generation, but there 

 is no evidence to prove that the original short-sightedness was a 

 modification. In all probability, short-sightedness is in its origin 

 a germinal variation, like so many other bodily idiosyncrasies. 



In regard to some diseases, such as rheumatism, it is often said 

 dogmatically by those who know little about the matter that 

 the original affection in the ancestor was brought about by some 

 definite external influence— such as a cold drive or a damp bed ; 

 but it seems practically certain that in all such cases we have 

 to do with an inborn predisposition, to the expression of which 

 the cold drive or the damp bed was merely the liberating stimulus, 

 comparable to the pulling of the trigger in a loaded gun. The 

 liberating stimulus is, of course, of great importance, both in 

 the case of the gun's discharge and the organism's disease, but 

 it only goes a little way towards a satisfactory interpretation in 

 either case. Not that we can explain the origin of rheumatism 

 or shortsightedness or any such thing — there is no explanation 

 in calling them germinal variations that cropped up ; but we 

 are almost certain that they never are modifications or acquired 

 characters. 



Herbert Spencer twits those who are sceptical as to the trans- 

 mission of acquired modifications with assigning the most flimsy 

 reasons for rejecting a conclusion they are averse to ; but when 

 Spencer cites the prevalence of short-sightedness among the 

 " notoriously studious " Germans, the inheritance of musical 

 talent, and the inheritance of a liability to consumption, as 

 evidence of the inheritance of modifications, we are reminded of 

 the pot calling the kettle black. 



