THE STORAGE OF FOOD-RESERVES 151 



Accessory Food-Products. We eat and drink many sub- 

 stances derived from plants which are not strictly food at 

 all. They are either consumed as aids to digestion, or, 

 because of their stimulating properties, they are employed 

 in the preparation of beverages. Others act medicinally 

 as drugs : 



(a) Spices and Condiments. These have little or no 

 actual food - value. They serve merely to stimulate 

 appetite or to render food more pleasing. The principles 

 contained in them arise as the result of certain chemical 

 changes taking place within the plant, and, most probably, 

 in connection with the respiratory functions. Respiration 

 begins with the inception of oxygen, and usually termi- 

 nates with the elimination of carbonic acid gas. If the 

 process is interfered with in any way, organic by-products 

 are formed, and if these turn out to be useful to the plant, 

 their formation tends to become habitual, and the dis- 

 position to produce them becomes hereditary. 



These substances are found in mustard (ground seeds of 

 Brassica nigra), pepper (ground fruits of Piper nigrum), 

 ginger (rhizomes of Zingiber officinale), cloves (dried 

 flower-buds of Eugenia caryophyllata), nutmeg (seed of 

 Myristica fragrans), capers (flower-buds of Capparis 

 spinosa), chillies (fruits of Capsicum annuum), water- 

 cress (shoots of Nasturtium officinale), horse-radish (rhi- 

 zome of Cochlearia Armoracia). 



The bases of flavourings are volatile oils. They are 

 generally obtained by distilling the parts of the plants 

 where they are present with water e.g., aniseed, caraway, 

 lavender, cloves, peppermint, rosemary, chamomile, 

 cinnamon, and lemon. The chemical composition of 

 some of these oils is known, and they can be artificially 

 prepared in the laboratory. 



(6) Beverages. Infusions of tea, coffee, and cocoa are 

 universally used as beverages. Alcohol is obtained by 

 fermenting sugar with yeast, either directly from a 

 vegetable sugar, or indirectly from starch. The range of 

 intoxicating drinks is almost as great as the range of man 

 himself. Sugary liquids, capable of fermentation, are 

 obtained from all kinds of plants -sprouting barley (beer 

 and whisky), grapes (wine, brandy, liqueurs), potatoes 

 (inferior spirits), sugar-cane (rum), agave (pulque), coco- 

 nut (toddy, arrack), honey (mead), etc. 



