82 Heredity and Social Progress 



them more readily than over other mediums. 

 Nerve cells are thus germ cells which, in 

 simpler organisms, would have become inde- 

 pendent beings. Wherever growth is active, 

 it absorbs the greater part of the nutrition that 

 the organism assimilates. Folds are formed, 

 and their growth develops enclosures before 

 the buds have time to develop, ripen, and 

 escape. There is an opposition between 

 growth and reproductioii. Where growth is 

 rapid, buds do not push out rapidly enough 

 to prevent the growing folds from reaching 

 and enclosing them by a fusion of the edges. 

 Reproduction is thereby delayed, and its amount 

 is much reduced below what it would be if 

 the earlier sex products were not confined and 

 transformed into nerves. 



If this thought is in a measure correct, form 

 is given to organisms through nerve growth. 

 Mere flesh would be little more than a mass. 

 Nerves grow in fixed directions and press 

 against the envelope that holds them in. Be- 

 ing sex products, they strive to break through 

 the envelope and free themselves. They 

 succeed if the envelope is not elastic, or 



