BOTANY FOR YOUNG PEOPLE. Ill 



supply of food will ensure its growth. The 

 germs that exist throughout the plant, are of 

 course, destitute of this supply, or the seed mak- 

 ing process would be unnecessary. Now to en- 

 sure the sprouting you must make the proper 

 kind of irritation, and place it in favorable cir- 

 cumstances to answer two objects, 1st, exciting 

 the germ, 2d, giving it sustenance while germi- 

 nating. 



Its excitemennt is easily produced, but the 

 other is more difficult. It is a law of vitality, 

 that if any part of a living body is excited the 

 vessels carrying fluid to that part will become 

 enlarged and carry much more than their usual 

 supply. Causing this first action around the 

 germ will give it the required food, and thus, 

 instead of perishing, it sprouts forth, and is either 

 a fresh branch on an old plant, or forms an en- 

 tirely new one. 



In order to make a layer, we are directed to 

 bend down a pliant branch without separating 

 it from the plant, and fasten it in the ground, 

 making a slight incision at the spot where it is 

 confined. The requisite irritation is thus pro- 

 duced, a flow of pure sap takes place towards 

 the part, the excited germ is supplied with food, 



