588 BIOLOGY AND HUMAN LIFE 



this mating numbered nearly 500 in about one hundred and 

 fifty years. Not one of these was of good ability ; 143 of them 

 were feeble-minded. After the war Martin Kallikak settled 

 down and married a normal young woman. The descendants of 

 this couple also numbered about 500 and not one of these was 

 feeble-minded. There are now about 70,000 feeble-minded 

 people in institutions of various kinds; they represent only 

 about a tenth of the actual incompetents who ought to be under 

 control. This means not only that these people fail to support 

 themselves, and so cost the rest of us their keep, but that they 

 cause additional loss through their irresponsible conduct, and 

 often become dangerous to others. 



Certain forms of insanity are believed to be inherited, but it 

 is likely that many people who become insane could be saved if 

 they had suitable guidance and environment earlier in life. 

 Much of the crime is also probably preventable through suit- 

 able training ; yet large proportions of criminals have defec- 

 tive constitutions, that is, hereditary weaknesses of mind or 

 make-up. 



422. Uncontrolled population. The advance of civilization, 

 by making it possible for a child or a very simple adult to 

 operate a complex but highly productive machine, has ob- 

 scured the fact that so many people are incompetent. In fact, 

 it has made it easier for the low-grade people to multiply than 

 for the high-grade. Intelligent young people who are anxious 

 to prepare themselves for high-grade service by continuing 

 their studies are obliged to postpone marriage for several years. 

 Feeble-minded people, who cannot in any case go far in school, 

 usually go to work at an early age ; they produce four or five 

 generations of large families in a century, whereas the pro- 

 fessional classes produce only three generations of very small 

 families. 



If the feeble-minded were in institutions where they would 

 get all suitable care and decent treatment, but no chance to 

 produce offspring, there would be a great saving. It would take 

 a very large amount of money to provide homes or farms for all 



