300 SECRETS OF ANIMAL LIFE 



" Out of approximately 600 living feeble-minded 

 and epileptic Jukes, there are now only three in 

 custodial care. It is estimated that at the end of 

 fifty years the defective germ-plasm would be 

 practically eliminated by the segregation of all of the 

 600." (3) A third proposal, to be considered very 

 critically, is to improve bad stock by letting it 

 mingle with good. If we were able, as we are not, 

 to distinguish beforehand between characters that 

 blend and characters that Mendelise, it might be 

 practicable to get a passable average man from a 

 good mother and a bad father, but in reference to 

 well-defined characters the trend of investigation 

 is strongly against any such experimenting. It is 

 probable that the very worst thing a man can do is 

 to taint good stock with bad. The children of such 

 unions may turn out not badly, if they are brought 

 up in conditions of wholesome nurture, and the taint 

 (if a unit-character) may be wholly absent in some 

 members of subsequent generations, but without 

 the aid of persistent selection it cannot disappear 

 from the lineage. When children genetically sound, 

 but by individual malnutrition weakly, are trans- 

 planted to good environment, they often do well; 

 and if they grow up, settle down and marry, no 

 stock is harmed. But Dr. Davenport justly doubts 

 the wisdom of sending " much bad germ-plasm to 

 good farming communities throughout our Middle 

 West." Dr. Davenport has done valuable service 

 to the science of genetics, but we wish he had not 

 written a sentence like this : " It is probable that, 



