MOVING MANUFACTURED FOODS 65 



other nuts, and in grains, olives, castor beans, one finds 

 oils stored in greater or less quantities. These are non- 

 nitrogenous foods which, however, since they are in- 

 soluble in water, are just as securely stored and are just 

 as immovable as starch or cellulose. Similarly, proteins 

 of various sorts insoluble in water are deposited in beans, 

 peas, and many other seeds, and in the stems and roots, 

 from which they may be removed only by digestion. 



Means of Moving Manufactured Foods. — Foods, 

 like the food materials, can be moved from cell to cell 

 only in solution ; but in solution the nitrogenous and non- 

 nitrogenous foods move readily throughout the cell, and 

 from cell to cell, through permeable membranes, in 

 accordance with the principles discussed in the preceding 

 chapter (VI). 



The Paths of Movement. — The foods are moved 

 (translocated) mainly along certain paths. These paths 

 may vary from season to season, as for example in the 

 sugar maple. In this tree the sugar moves down from 

 the leaves to the places of storage through the inner bark 

 throughout the summer; but in the spring it is mainly 

 through the wood that the sugar-containing sap is moved 

 from the places of storage upwards to the swelling buds. 

 Gne may often find that the inner bark of trees or shrubs 

 tastes sweet, whereas there is no such flavor in the wood. 

 One may sometimes notice, on pulling apart a stalk of 

 growing wheat, oats, or barley, in the afternoon of a 

 warm sunny day in early summer, that the joints are both 

 sweet and tender. In the early morning, before the 

 leaves have made any food, and when the grain is 

 nearly ripe, there would be no sweetness in the stalks, 

 because there would be no sugar in transit. The inner 

 bark, or phloem, of the vascular bundles, is the conduct- 

 ing tissue through which most of the sugar is moved from 

 places of manufacture to places of storage; whereas the 

 wood may be the path of movement of sugar, etc., from 

 the places of winter storage to the regions of 

 spring growth. 



