DISTINCTION BETWEEN ANIMAIS AND PLANTS, n 



In these facts must be found 'the true and funda- 

 mental distinction between animal and plant. Yet 

 even here we may find some exceptions to the rule. 

 Plants of the class called Fungi, like animals, require 

 at least a proportion of ready-made food : they feed iu 

 fact on animal or vegetable matter, some preferring 

 sugar or jam, some animal substances, while some 

 even attack living plants or animals. As has been 

 already mentioned, these plants also give out per- 

 ceptible quantities of 00^ at all times, as other plants 

 do only at night ; and so do growing flower-buds and 

 germinating seeds. In all these cases there is an ac- 

 companying perceptible evolution of heat, although in 

 ordinary plant life the evolution of heat, like the produc- 

 tion of CO2, is so small as to be scarcely perceptible. 



Again, there are plants of much higher organization, 

 which, in addition to the usual modes of root-feeding 

 and leaf-feeding, take in animal food by surface ab- 

 sorption: such are the Fly-trap, and the Sundew, 

 whose leaves have a special trap apparatus, sensitive 

 like that of the flowers already mentioned, by means of 

 which they catch flies, and absorb their juices. The 

 Butterwort or Bog Violet {Pinguicula), which was 

 formerly used as rennet '^ in England and is even now 

 so used in Norway, has slimy leaves with incurved 



' Rennet is the substance used in cheese-making to curdle 

 the milk. Usually it is the lining of a calf's or pig's stomach, 

 the gastric juice of which curdles the milk just as it would in 

 the preliminary process of digestion ; but there are a number 

 of plants which may be used to produce the same efiect. 



