40 



A PRIMER OF BIOLOGY 



of storage, and the storage form is naturally in most 

 cases an insoluble one. The plant on that account 

 also possesses enzymes, proteid, carbohydrate and 

 fat-transforming ferments, manufactured in some 



cases in special glands, but 

 more commonly in the 

 cells which contain the sub- 

 stances to be transformed. 

 Even in the animal, diges- 

 tion may take place within 

 individual cells, as, for 

 example, of glycogen a 

 starch-like compound in 

 the cells of the liver. 

 Fundamentally, therefore, 

 the digestion of food in 

 the plant and the animal 

 is carried out on the same 

 principles, and the only 

 difference really lies in 

 the mode of production of 

 the secretions, associated 

 with the absence of any 

 specialised digestive tract 

 in the plant. 



It must also be noted 

 that there are certain 

 plants (carnivorous plants) 

 whose leaves are greatly 



FIG. 15. Drosera. (Half 

 natural size. ) 



modified in form from ordinary terrestrial types 



and which possess, at least in some cases, definite 



nivorous cavities or pockets into w T hich insects are, by a 



plants. variety of methods, induced to enter. These 



chambers are virtually stomachs and their walls 



are more or less lined by glands which secrete enzymes 



