INTRODUGTION. 5 



circTilatioii, and nothing approaching to a nervous system. 

 Most plants absorb inorganic food, such as carbonic-acid 

 gas, water, nitrate of ammonia, and some phosphates, silica, 

 etc., all of these substances being taken up in minute 

 quantities. Low plants live on dead animal matter, and 

 promote the process of putrefaction and decay, but the food 



Fio. 5.— Part of a Slime-mould. (Magnified 350 timesi.) 



of these organisms is inorganic particles. The slime- 

 moulds (Fig. 5), however, envelop the plant or low ani- 

 mals, much as an Aniceba throws itself around some living 

 plant, and absorbs its protoplasm; but slime-moulds, in their 

 manner of taking food, are an exception to other moulds. 

 The lowest animals swallow other living animals whole or 

 in pieces; certain forms near Ammia bore into minute 



