THE YOUNG NATURALIST. 



175 



out to be a mistake, it was known even then 

 that plants could not take up any kind of 

 solid matter, but he thought that decayed 

 vegetation produced carbonic acid, which 

 when dissolved in water might be taken up by 

 the roots of the plant. But recent investiga- 

 tions have brought out different theories, and 

 even our present ideas cannot be looked upon 

 as absolutely perfect, as fresh discoveries are 

 made, and new facts found out they will have 

 to give way and others take their place. All 

 the carbon of which the plant is composed is 

 taken in through the pores of the leaves in the 

 shape of carbonic acid gas, and these chloro- 

 phyl grains have a remarkable affinity for this 

 gas. See how beautifully the order of nature 

 is balanced. Every time we breathe we in- 

 hale oxygen and nitrogen, but when we exhale 

 we give off carbonic acid gas, a poisonous gas, 

 known to miners as " choke damp." This is 

 not only done by ourselves but by lower 

 animals as well, and what man and animals 

 are doing now, man and animals have been 

 doing ever since they existed, and millions of 

 years before man made his appearance, 

 animals carried on the same work, and if no 

 antagonism to this poisoning had existed the 

 atmosphere would soon have become so much 

 corrupted that it would have been impossible 

 for an animal to have lived in it for five 

 minutes. But all this has been rectified, for 

 that which the animals give off the plants 

 want, and so the true balance is kept up, and 

 the atmosphere is to-day probably just the 

 same as it was when plants and animals first 

 began to live. The plants take in carbonic 

 acid gas and liberate oxygen ; animals take in 

 oxygen and liberate carbonic acid gas. But 

 it is only during the sunlight that plants are 

 active, during the night they are dormant, 

 except that they liberate a very small quantity 

 of carbonic acid gas, and from this fact some 

 people have imagined that it is hurtful to keep 

 plants in sleeping rooms, but the quantity of 

 gas evolved during the night is so small that 

 no bad results need be feared on this account. 

 Plants generally feed upon inorganic sub- 



stances, and we want a scientific system of 

 farming. Now the farmer goes by the rule of 

 thumb, but we want to instruct him so that he 

 might know when certain soils are adapted to 

 the growth of certain plants, and so on, But 

 there are certain plants which feed upon 

 organic substances, we know some plants, 

 especially the Sundew and Venus' fly-trap, 

 which catch flies. If you will examine a leaf 

 of Sundew you will find that it is studded 

 with little bristles, each one of which has a 

 knob at the end, and these knobs have the 

 power of secreting a sticky substance, These 

 bristles are longest round the edges of the 

 leaf, while in the centre there is only the knobs. 

 Insects are attracted by the gay color of the 

 leaf, and as soon as they settle upon it they 

 find themselves entangled by this sticky bird- 

 lime, and the long bristles at the edges then 

 begin to bend over until the fly is completely 

 enclosed in their folds, where it is held until 

 it is digested, and appropriated to the use of 

 the plant. The process of digestion is exactly 

 the same as that which takes place in our own 

 stomachs. Another plant of this kind is 

 Venus' fly-trap, it grows in Carolina. The. 

 leaf of this plant consists of two lobes with 

 bristles along the edges, and when a fly settles 

 upon it the lobes close instantly and the fly is 

 imprisoned between them, where it is held 

 until it is digested. It may be asked, Are 

 the plants any better for catching these flies ? 

 and Mr. Darwin has answered this question 

 in a most satisfactory manner : he has shown 

 that those plants fed upon flies produce more 

 flowers, more seed, weigh heavier, and are 

 altogether stronger plants than those which 

 had no flies. There are many other plants 

 which catch insects by various means, some 

 of them have vessels containing water, and 

 when an insect goes to peep into the pitcher, 

 if it makes the slightest slip it topples over 

 into the water, and when it is once there it 

 finds it very difficult indeed to get out again. 

 It is a very interesting subject, and one that 

 is well worth the careful study of any intel- 

 ligent young man or woman. 



