22 REPRODUCTION 



from the above that budding is a form of division or 

 reproduction, in which an actual portion of the mother 

 organism forms the beginning. This portion that goes 

 into the young at the start is small, much less than the 

 one-half that goes to the young in division. Much of the 

 nutrition the mother cell takes up after the bud is formed 

 passes on into the young, because of the close connection 

 betw^een the bud and the mother cell. The yeast does 

 not do so much for its bud at the start as is done in 

 fission; but it keeps up its help longer. 



This is the simplest form of budding we find. It is, 

 however, a very good picture of the essential nature of it 

 even in the more complex plants and animals in which 

 we find it. Always in buds some of the very structure of 

 the parent organism grows directly into a small, young 

 offshoot or offspring; and a close, nourishing connection 

 remains by which the young grows at the expense of the 

 parent, as a kind of temporary parasite on the parent. 

 Sometimes they separate after a while and live 

 independent lives. In other cases the young remain 

 attached permanently to the old organism until the young 

 themselves are mature and produce other buds. When 

 the whole series of generations remain together 

 permanently like this we call it a colony. 



4. A More Complex Bud: Hydra. This little fresh- 

 water polyp is found widely in the ponds and lakes of 

 North America and is used very commonly in the 

 laboratory work in zoology. We have in it an animal of 

 many cells as simple as the student is likely to find. It is 

 practically a tube open at one end and closed at the other, 

 the wall of which is two cells thick. Near the open end, 

 the wall is pushed out in a number of hollow tentacles, 

 whose cavities are continuous with the cavity of the 

 animal. When the animal has come about to its mature 

 size and is getting an abundance of food, and the other 

 conditions are right, portions of the body wall may 

 pouch outward with the general cavity of the body 



