33^ DARWINISM AND THE PROBLEMS OF LIFE 



owing to some chance increase in its food-supply, it is 

 particularly favoured in the struggle. If it becomes 

 smaller, it is gradually crushed out, because the food 

 is taken from it by its neighbours. 



Hence on this theory there can only be a limited 

 amount of nourishment in the germ. If it were 

 inexhaustible, a tendency to increase in the determinant 

 of a useless organ would not be prejudicial to its neigh- 

 bours, as they also would have sufficient food. In this 

 way organs would not be reduced to a rudimentary 

 condition, since the rising and falling variations of the 

 determinants would neutralise each other in the general 

 crossing, as we have already seen. 



According to the theory of germinal selection, there- 

 fore, the amount of nourishment in the germ is limited. 

 But each determinant must have enough to maintain 

 itself. When, therefore, the determinant of a useless 

 organ becomes weaker and weaker in each succeeding 

 generation, what becomes of the food that formerly went 

 to it? As we saw that a determinant only becomes 

 stronger by taking food away from its neighbours, so 

 when they become weaker, it must mean that their 

 neighbours have taken food from them. Thus the 

 determinants that are contiguous to the determinant of 

 a useless organ will absorb the nutrition that formerly 

 went to it. They will grow; and as they become 

 stronger they will, according to the theory, continue 

 to grow, and so will their respective organs. Hence, 

 on this theory, the parts adjacent to a rudimentary 

 organ in the body must steadily increase in size. For 

 the same reason the parts surrounding a growing organ 



