968 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



THE DIETETIC VALUES OF FOOD-STUFFS PREPARED BY 



PLANTS 



By Rev. Professor G. Henslow, M.A., F.L.S., V.M.H., &c. 



[Delivered November 4, 1902.] 



The necessity of food may be regarded from two chief points of view : 

 first, the growth and restoration of bodily tissues ; and secondly, the 

 supply of energy. Though such (nitrogenous) foods as can accomplish the 

 former may also furnish fat and supply force, yet the value of non-nitro- 

 genous foods may be usefully regarded as having the special function of 

 force-producing, though they can also supply fat as well, in the building 

 up of the structures of the body. 



The nitrogenous food-stuffs, called collectively albuminoids, consist of 

 several substances in plants, such as fibrins, e.g. gluten-fibrin, associated 

 with gliadin and mucedin in the gluten of wheat ; * while legumin and its 

 allies are found in the seeds of leguminous plants. Regarding the value 

 of the vegetable albuminoids as food, it must be borne in mind that they 

 are not so readily acted upon and absorbed as animal albuminoids. This 

 is partly due to the fact that the aleurone grains, as the reserve form of 

 albuminoids is called by botanists, are included within the cells composing 

 the cellular tissue. Cellulose, of which the cell-walls are composed^ more 

 or less resists the action of ferments ; so that it is important that wheat 

 and other kinds of grain should be completely ground, in order to liberate 

 the cell-contents. Secondly, a moderate quantity only of such foods 

 should enter the daily diet, or else a certain portion will escape digestion. 



The non-nitrogenous food-stuffs consist of carbon united with hydro- 

 gen and oxygen in the same proportions as these two constitute water. 

 They are "cellulose," of which the cells are composed; "starch"; 

 "inuline," characteristic of Composite, as the 'Jerusalem Artichoke'; 

 " dextrine, " which is an intermediate condition between starch and glucose, 

 produced by the ferment, diastase ; " levuline " in Jerusalem Artichokes; 

 "mucilage," and varieties of "sugar." As none of these contain any 

 nitrogen, they are powerless of themselves to restore waste in the numerous 

 parts of the human body which depend upon that element ; but they 

 can all contribute to the formation of fat. 



Several minerals are also of great value in the human economy. The 

 majority do not form so obvious a feature as does lime in the structure of 

 bones, but are diffused throughout the system. Similarly are they in 

 growing plants. But analyses show that they become localised in seeds, 

 where they are laid up with temporary reserve food. Therefore the 

 mineral value of such special parts which constitute human food should 

 not be lost sight of from a dietetic point of view. Sodium chloride, or 



* This is easily obtained by washing some Hour with cold water in a sieve or cloth, 

 which allows the water to carry off the starch ; the gluten is then left behind. 



