136 THE MENDEL JOURNAL 



3. — "Unit Qualities, WHICH determine value, are 



DETERMINED BY HEREDITY AND NOT BY ENVIRONMENT." 



I come now to the most serious of all my ol)- 

 jections to "A Plea for Virile Sentiment." This 

 objection rests on what seems to me the very 

 remarkable nature of the author's assumptions as 

 to the unit qualities of the mental world. 



If I have not misunderstood Mendelism alto- 

 gether, it appears that no application of it can be 

 made with certainty until the experimentor has dis- 

 covered what the transmissible unit qualities are. 

 For instance, the tendency of a sweet pea to be a 

 dwarf is such a quality, but the tendency of a 

 j)etunia to be white is not a imit but results from a 

 combination of factors ; and the prophecies about 

 inheritance must be quite different in these two 

 cases. Further, the power of a muscle to do very 

 hard work is not asserted to be transmissible if that 

 power has been acquired by exercise. The capacity 

 for developing such a power may be inherent, l)Ut 

 the power itself is not inherent Ijut acquired, and 

 no prophecies about its inheritance can be made so 

 far as Mendelism is concerned. If then we are to 

 prophesy about the inheritance of mental character- 

 istics, it will be all-important to find out the inherent 

 units. Now what I urge from the side of psychology 

 is this : that, except to a minute extent, nobody 

 can say at present what the units are ; that 

 scarcely any of the qualities instanced by Mr. Mudge 



