8 NATURAL INHERITANCE. [chap. 



now made of it will be better understood through an illus- 

 tration. Thus, many of the modern buildings in Italy 

 are historically known to have been built out of the 

 pillaged structures of older days. Here we may observe 

 a column or a lintel serving the same purpose for a 

 second time, and perhaps bearing an inscription that 

 testifies to its origin, while as to the other stones, though 

 the mason may have chipped them here and there, and 

 altered their shapes a little, few, if any, came direct 

 from the quarry. This simile gives a rude though true 

 idea of the exact meaning of Particulate Inheritance, 

 namely, that each piece of the new structure is derived 

 from a corresponding piece of some older one, as a lintel 

 was derived from a lintel, a column from a column, a 

 piece of wall from a piece of wall. 



I will pursue this rough simile just one step further, 

 which is as much as it will bear. Suppose we were 

 building a house with second-hand materials carted 

 from a dealer's yard, we should often find considerable 

 portions of the same old houses to be still grouped 

 together. Materials derived from various structures 

 mig-ht have been moved and much shuffled together 



o o 



in the yard, yet pieces from the same source would 

 frequently remain in juxtaposition and it may be 

 entangled. They would lie side by side ready to be 

 carted away at the same time and to be re-erected 

 together anew. So in the process of transmission by 

 inheritance, elements derived from the same ancestor 

 are apt to appear in large groups, just as if they had 

 clung together in the pre-embryonic stage, as perhaps 



