20 



ANIMALS AND PLANTS. 



of complex compounds, and is essentially an oxidation process, by 

 which potential energy is converted into kinetic (movement, produc- 

 tion of heat, light). The vital activity of plants, on the contrary, is 

 based, so far as it relates to assimilation, on synthesis, and is 



essentially a process of reduction ; 

 under the influence of which the 

 energy of warmth and light is stored 

 up, kinetic energy being converted into 

 potential. 



Nevertheless, this difference also is 

 not applicable as a test in all cases. 

 Recently the attention of investigators 

 has been turned, especially by Hooker 

 and Darwin,* to the remarkable nutri- 

 tive and digestive processes in a group 

 of plants which Avere first observed a 

 hundred years ago (Ellis). The plants 

 in question catch, after the manner of 

 animals, small organisms, especially in- 



Pi .7.-L'eafof Droserarotundifolia, sects > and absorb from them through 

 with partially contracted tentacles the glandular surface of their leaves 



(after Darwin). , . 



the organic matter after a chemical 



process resembling animal digestion (leaves of the Sun-dew, Drosera 

 rotundifolia, and the fly-catcher, Dioncea muscipula. Figs. 7 & 8). 



Many parasitic plants and 

 almost all fungi have not, 

 however, in general, the 

 power of making organic 

 substances from inorganic, 

 but suck up organic juices ; 

 and in taking up oxygen 

 and giving out carbonic 

 acid, they present a respi- 

 ratory process resembling 

 that found in animals. 



It was established by 

 Saussure's observations that all plants require oxygen at certain 

 intervals ; that in those parts of plants which are not green, not 

 possessing chlorophyll, and alt-o in the green parts in the absence 

 of sunlight, i.e. at night, a consumption of oxygen and exhalation 

 * Compare especially Ch. Darwin, " Insectivorous Plants." London, 1875. 



FIG. 8. Leaf of Dionaea muscipula in expanded 

 condition (after Darwin). 



