THE ORIGIN OF WALNUTS. 169 



common shell against a stone or otherwise ; 

 and, if he is successful in this process, he 

 must afterwards break the separate sharp- 

 edged inner nuts with his teeth a perform- 

 ance which is always painful and often in- 

 effectual. 



Yet it is curious that nuts and fruits are 

 really produced by the very slightest varia- 

 tions on a common type, so much so that the 

 technical botanist does not recognise the 

 popular distinction between them at all. In 

 his eyes, the walnut and the coco-nut are not 

 nuts, but ' drupaceous fruits/ just like the 

 plum and the cherry. All four alike contain 

 a kernel within, a hard shell outside it, and a 

 fibrous mass outside that again, bounded by 

 a thin external layer. Only, while in the 

 plum and cherry this fibrous mass becomes 

 succulent and fills with sugary juice, in the 

 walnut its juice is bitter, and in the coco-nut 

 it has no juice at all, but remains a mere 

 matted layer of dry fibres. And while the 

 thin external skin becomes purple in the 



