ON GARDENING 



and sugars. These make up the chief bulk of such 

 tubers and roots as potatoes and carrots and 

 parsnips, and the main nutritious matter of the 

 principal garden vegetables, except, as just inti- 

 mated, that peas and beans have a relatively high 

 proteid or nitrogenous content. 



After what has been said, it will be understood 

 that the starch and sugar content of the potato, for 

 example, is not developed in the tuber itself, but 

 is manufactured in the leaf of the plant and is then 

 carried down in the elaborated sap that runs as a 

 sort of return current to the roots and is there 

 deposited for the uses of the new plant next season. 



In the case of the carrot and parsnip, the same 

 thing, of course, is true. Here a large root, with 

 its deposit of starch and sugar, is designed to live 

 through the winter and next season to supply such 

 nourishment for the plant as will enable it to take 

 on rapid growth and to develop a large quantity 

 of seeds. These plants are biennials and do not 

 fruit in their first season. It is this fact that has 

 been taken advantage of by man in developing 

 their roots and diverting them to his own uses. 

 Principles versus Methods 



In all this, it will appear, we have said nothing 

 as to practical methods of gardening. But I have 

 thought that a clear outline of the principles in- 

 volved in the all-important matter of the nutrition 



[37] 



