THE CELL 43 



starch, the well-known substance which is used for 

 dressing linen and also in the kitchen. Thus we have 

 separated the flour, simply by washing it, into two of 

 its components : gluten and starch. If we had mixed 

 the flour with ether and let it stand, then poured off 

 the ether and let it evaporate in an open dish, 

 we should have obtained an oily residue. Thus flour 

 or grains of corn consist chiefly of three substances : 

 gluten, starch, and oil. 



The methods of separating these substances which 

 have just been described may serve as. a rough but 

 obvious example of a so-called proximate analysis. 

 In such an analysis we try if possible to extract sub- 

 stances, without altering them, by taking advantage of 

 their properties of dissolving or not dissolving, of 

 volatilising, crystallising, and so on. 



These three bodies, starch, gluten and fat, may be 

 taken as representatives of the three principal and 

 most widely diffused groups of vegetable substances. 

 These groups are known as carbohydrates, albumin- 

 oids, and fats. Other substances are generally met with 

 either in comparatively small quantities or else in 

 exceptional organs or plants, and consequently do not 

 affect the general phenomena of vegetable life. Here 

 is a table giving the proportions in which these proximate 

 constituents are present in various widely differing 

 vegetable products. These analyses fully endorse what 

 has just been said about the large mass of the plant 

 consisting of the three classes of compounds which have 

 been enumerated. 



IN IOO PARTS. CLOVER WHEAT LUPINE FLAX 



plant. flour. seeds. seeds 



(i.e. linseed). 



Carbohydrates . i6'6^ 74-8 / 45 '5 "2. 62-2^ 

 Albuminoids . 

 Oils 



Ash ... 

 Water 



