PRODUCTIVE GARDENING 95 



be said to center on the production of the non- 

 nitrogenous carbon compounds, starch and vari- 

 ous sugars, the creation of which in the leaf of 

 the plant we have just witnessed. For the chief 

 products of the vegetable garden (with the nota- 

 ble exception of peas and beans) contain only 

 a small proportion of the nitrogenous matter 

 which the food specialist names protein. We 

 depend for our nitrogenous foods largely upon 

 the animal world. 



The products of the vegetable garden are 

 stores chiefly of carbohydrates, that is to say 

 of starches 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, ex- 

 cept, as just intimated, that peas and beans have 

 a relatively high proteid or nitrogenous content. 



After what has been said, it will be under- 

 stood that the starch and sugar content of the 

 potato, for example, is not developed in the tu- 

 ber 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 



