HOW PLANTS DRINK. 69 



and boggy soils there is generally ajlack_qf these_ 

 necessary earth-given elements of "protoplasm ; 

 and natural selection has therefore favoured 

 any device in the plants which grow in such 

 places for obtaining them elsewhere. This they 

 do as a rule by catching insects, killing them, 

 sucking their juices, and using them up as 

 manure for manufacturing their own protoplasm 

 and chlorophyll. Our pretty little English 

 sundew is one of these cruel and perfidious plants 

 (Fig. 10). Its leaves are round, and thickly 

 covered with small red hairs, which are rather 

 bulbous at the end, and very sticky. The 

 bulbous expansions, in point of fact, are small 

 red glands, which exude a viscid digestive 

 liquid. When a small fly alights on the leaf, 

 attracted by the smell of the sticky fluid, he is 

 caught and held by its gummy mass ; the hairs 

 then at once bend over and clutch him, pouring 

 out fresh slime at the same time, which very 

 shortly envelopes and digests him. In the 

 course of a few hours the leaf has sucked the 

 poor victim's juices, and used them up in the 

 manufacture of its own protoplasm. 



Many other insect-eating plants exist in the 

 marshy soils of other countries. One of the 

 best-known is the Venus' 's fly -trap of tropical 

 or subtropical North America. In this curious 

 plant the leaf is divided into two portions, one 

 of which forms a jointed snare for catching 

 insects. It is hinged at the middle ; and when 

 a fly lights upon it, the two edges bend over 

 upon him, and the bristles on the margin 

 interlock firmly. As long as the insect struggles 



