PEOPLE FOR THE EARTH 



58s 



careful studies of hundreds of family histories can tell us, 

 heredity of mental qualities and emotional tendencies is the 

 same as heredity of physical characters (see Fig. 243). This 

 is what we should expect, since these mental and moral quali- 

 ties depend so closely upon the structure of the nervous system 

 (including the brain) and the workings of the endocrin glands. 



HEREDITY IN MAN 



420. Good stock. Someone has said that the most valuable 

 crop in the world is the total of babies born every year. Many of 

 these babies die very soon after they are born (see section 282). 

 With better care more and more are saved every year, yet some 

 people have gone so far as to say that it would be best to leave 

 the babies and the mothers to themselves, so that only those 

 would survive the difficult period who were really fit. There are 

 many babies who could not survive the first few weeks without 

 help, but who would grow up to be very valuable men and 

 women ; and, on the other hand, we know that many babies 

 survive very bad conditions, and then turn out to be anything 

 but desirable. Nevertheless a civilized community can do no 

 less than give every baby the fullest opportunity to show what 



