OTHEE METHODS OF OBTAINING FOOD 209 



slightly concave and fold over quickly, the teeth interlock, 

 and the cavity is closed. If the contact has been made by 

 an insect, it is captured and imprisoned between the lobes. 

 The closing is fairly rapid, taking perhaps ten seconds. 

 All over the upper surface of the lamina secreting glands 

 are found, whose secretion is similar to that of Drosera. 

 If the leaf encloses nitrogenous digestible matter, such 

 as the body of an insect, the prison remains closed for 

 some considerable time, and the glands surround the prey 

 with the digestive fluid, the products of its decomposition 

 being absorbed by the gland-cells. 



These mechanisms for the digestion and absorption of 

 proteid substances are seen to be extremely complex. Evi- 

 dence of such digestion and absorption is shown also by far 

 humbler plants without any differentiated structure. Many 

 Fungi and Bacteria when cultivated in solutions containing 

 native proteids, such as albumin or globulin, are able to 

 effect their digestion by the secretion of a similar enzyme to 

 those of the plants already described. They subsequently 

 absorb the peptone or the amido-acids which result from 

 such action. Nor is proteid material alone affected in this 

 way by these humbler plants. They derive their carbo- 

 hydrate supplies from their environment in the same way 

 as their proteid ones. Many of the filamentous fungi 

 possess the property of forming digestive enzymes, which 

 attack sometimes starch, sometimes inulin, sometimes vari- 

 ous sugars which are not immediately available for nutri- 

 tion, sometimes other more complex substances, all of 

 which undergo this external process of digestion, the result- 

 ing bodies being subsequently absorbed. 



In the earlier pages of this chapter we drew attention 

 to the fact that it was not at all uncommon to find two 

 plants closely associated together, with different degrees of 

 completeness, with a view to their co-operation in carrying 

 out some of these abnormal processes of nutrition. We 

 may now study these relationships a little more fully. 



The simplest cases of the dependence of one plant 



p 



