ARE ACQUIRED CHARACTERS HEREDITARY? 329 



it.— At first sight this seems hair-splittin^^ ])ut it is a crucial jioint. 

 Through his vigorous exercise the blacksmith develops a muscular 

 arm worthy of admiration; the shoemaker acquires skeletal and 

 muscular peculiarities less admirable. There are many permanent 

 and profound modifications associated with particular occupations. 

 Are we to believe, it is asked, that the occupation of the parents has no 

 influence on the offspring? Are we to believe, it is asked, that the 

 children of soldier, sailor, tinker, tailor, are in no way affected by the 

 parental functions ? 



It would be interesting to have precise data in regard to this, l)ut it 

 is generally admitted that when parents have healthful occupations 

 their offspring are likely to be more vigorous. The matter is comi)li- 

 cated by the difficulty of estimating how much is due to good nurture 

 before and after birth. It is not unlikely, too, that some profound 

 parental modifications may influence the general constitution, may 

 even affect the germ-cells, and may thus have results in the offspring. 

 But unless the offspring show peculiarities in the same direction as the 

 original modifications, we have no data bearing precisely on the ques- 

 tion at issue. 



A belief in the inheritance of modifications was perhaps expressed 

 in the old proverb, "The fathers have eaten sour grapes, and the 

 chfldren's teeth are set on edge" — a proverb which Ezekiel with such 

 solemnity said was not any more to be used in Israel. Now if " setting 

 on edge" was a structural modification, and if the children's teeth were 

 "set on edge" as their fathers' had been before them, there would be a 

 presumption in favour of the transmission of this acquired character, 

 though it would be stiff necessary to inquire carefully whether the 

 children had not been in the vineyard too. But if, as Romanes said, 

 the children were born with wry necks, we should have to deal with 

 the inheritance of an indirect result of the parent's vagaries of appetite, 

 and not with any direct representation in inheritance of the particular 

 modification produced in the paternal dentition. 



Misunderstanding IX. — Appealing to data from not more than two 

 generations. — It has often been pointed out that animals transported 

 to a new country or environment may exhibit some modification 

 apparently the result of the novel influence, and that their offspring 

 in the same environment may exhibit the same modification /;/ a 

 greater degree. Thus sheep may show a change in the character and 

 length of their fleece, and their progeny may show the same change 

 more markedly. 



