540 



The Journal of Heredity 



reaching maturity. In the most highly 

 civihzed States the lives of these un- 

 fortunates are preserved by eharity, 

 and in not a few they are allowed to 

 reproduce, and thus natural selection, 

 the great law of evolution and progress, 

 is set at naught. It is within the power 

 of society to eliminate from re])roduc- 

 tion this dependent class. 



How can the number of defectives 

 born from defective parents be reduced ? 

 Evidently if these defects are heredi- 

 tary it can be done only by preventing 

 their breeding, since in modern society 

 defective? cannot be destroyed by 

 Spartan methods. Many ways have 

 been recommended and a few have been 

 tried to accomplish this end, but they 

 all come under two categories: (1) 

 Segregation to prevent the union of the 

 sexes, (2) sterilization or other means 

 to prevent conception following sexual 

 union. Such methods if rigidly applied 

 to all defective or abnormal persons 

 would doubtless reduce the number of 

 "children receiving a faulty heritage 

 from their parents," but since it is im- 

 possible for reasons indicated above to 

 apply these methods to any except the 

 most seriously defective class, which is 

 usually dependent upon public care or 

 private charity, and since in general 

 the birth rate at present among such 

 defectives is not large, no great change 

 in the number of births of defective 

 children through such elimination need 

 be anticipated. And this is cs])ccially 

 true since children inherit not merelv 



carry the defect in their germ plasm and 

 may transmit it to their descendants 

 though not showing it themselves. 

 Such persons are more dangerous to 

 society than the defectives themselves. 

 And yet it is ]3robably impossible 

 rigidly to exclude them from reproduc- 

 tion 



Finally, it is usually difficult and often 

 impossible to decide whether a given 

 defect is due to heredity or to environ- 

 ment; if it is due to the latter the 

 methods adopted for its prevention 

 must be wholly different from what they 

 would be if it is due to the former 

 cause. Experiments on guinea-pigs, 

 rabbits and other animals show that 

 serious defects may be j^roduced in off- 

 spring by the action of alcohol and 

 drugs on either or both of the 

 parents before conception, and Forel 

 with his wide experience in such 

 matters does not hesitate to main- 

 tain that the effect of alcohol on 

 either or both of the parents at the 

 time of conception is one of the most 

 fruitful causes of monstrous or defec- 

 tive children. No doubt there are 

 many other environmental causes of 

 defects in children, such as infection, 

 malnutrition, injury, etc., at various 

 stages in their development. 



Dr. Henry H. Goddard, of the Train- 

 ing vSehool at Vineland, N. J., has 

 kindly furnished me with the following 

 figures regarding the mental condition, 

 so far as it has been investigated, of the 

 parents of the inmates of that institution : 



Number of families investigated 337 or 100% 



Both parents feeble-minded 57 or 16. 9% 



One parent feeble-minded and other normal 43 or 12. 8% 



One parent feeble-minded and other unknown 54 or 16.0% 



Family history of feeble-mindedness 154 or 45. 7% 



Both parents normal 90 or 26. 7% 



One parent normal, the other unknown 47 or 13. 95% 



Both i)arents unknown 46 or 13.65% 



the traits which their parents .show, but 

 also those family traits which are carried 

 along in the germ plasm in a latent or 

 recessive form, waiting only for an 

 opportunity to become i)atent. The 

 study of heredity shows that the normal 

 brothers and sisters, or even more dis- 

 tant relatives, of defective persons ma\' 



1 am indebted to Dr. Martin \V. 

 Barr of the Pennsylvania Training 

 School at Elwyn, Pa., for an extensive 

 etiological table which he has prc]jared 

 showing the i:)robal3le causes of men- 

 tal defect in more than 4,000 cases, 

 from which I quote the following simi- 

 maries : 



