GENERAL INTRODUCTION 



for the size of the new peristome that is formed, but the latter becomes 

 larger, until the characteristic form has been reached. The change 

 in form of the stentor may take place in a few hours, and the result 



FIG. 8. After Gruber. Stentor cceruleus. A. Cut into three pieces. /?. This row shows regen- 

 eration of anterior piece. C. This row shows regeneration of middle piece. D. This row 

 shows regeneration of posterior piece. 



is brought about, not by the development of new protoplasm over the 

 cut-end, but by a change of the old protoplasm into the new form. A 

 similar experiment is shown in Fig. 8, in which a stentor was cut into 

 three pieces, each piece containing a part of the old nucleus. 



REGENERATION IN PLANTS 



In the higher plants the production of a new plant from a piece 

 takes place in a different way from that by which in animals a new 

 individual is formed. The piece does not complete itself at the cut- 

 ends, nor does it change its form into that of a new plant, but the 

 leaf-buds that are present on the piece begin to develop, especially 

 those near the distal end of the piece, as shown in Fig. 32, A, and 

 roots appear near the basal end of the piece. The changes that take 

 place in the piece are different from those taking place in animals, 

 but as the principal difference is the development of the new part 

 near the end, rather than over the end, and as in some cases the 



