GRAFTING 



221 



Budding and grafting. A, bud; B, stock; 

 C, budding completed ; D, two scions in place ; 

 E, grafting completed by coating of wax. 



escape from its enemies, and for a new claw to form later on the 

 stump of the old one. The common swift, a lizard, will throw off 

 its tail to escape being 

 caught; a new tail may 

 later be regenerated. 



Grafting. — A familiar 

 method of multiplying 

 desirable varieties of fruit 

 trees is by grafting. This 

 consists in applying a 

 portion of a tree of the 

 desired variety (called 

 the scion) to another tree of a nearly related kind (called the stock) . 

 The two parts must be so placed that there is a connection between 

 the tubes in the outer wood and in the bark of each. Why? 

 Peach, apricot, apple, and pear trees are often grafted. Another 

 similar method is called budding. A bud of the desired tree is 

 inserted under the bark of the stock. The branches growing from 

 the bud or scion will bear the same variety of fruit as if they had 

 remained on the original tree. Grafting and budding^ as we shall 

 see later, are widely used by plant breeders to perpetuate desir- 

 able kinds of plants. 



Grafting is also practiced in animals. Hydra, worms, insects, 

 and frogs all have been used experimentally. Surgeons graft 

 skin after a severe burn, or graft glands in sheep, goats, or other 

 animals and rarely in man„ In all of these cases the same thing 

 takes place as when we cut ourselves and the wound heals ; new 



tissues are formed by 

 the growth of cells. 



Vegetative Propa- 

 gation and Reproduc- 

 tion. — Since all of the 

 above methods of 

 growth are caused by 

 the division of body 

 cells, we speak of them 



Grafting. Professor Morgan of Columbia grafted ^g examples of VCgC- 

 parts of earthworms and produced: 1, a very long , ^ _ ^ 



worm ; 3, a two-tailed one ; 5, a very sliort one. tative propagation or 



