342 Florence Peehl 



es 



current has nothing to do with the order of appearance of the 

 hydranths on the ends-of the grafts. We must seek an explana- 

 tion elsewhere. I believe that it requires a large amount of energy 

 to construct a new hydranth. In order to produce sufficient 

 energy certain metabolic processes are set up. These processes 

 must begin as soon as the wound closes. If the condition of the 

 stem is such that sufficient energy can be produced, hydranths are 

 formed at once, if not, the development is delayed until there is 

 enough energy. When two pieces are grafted together, some of 

 this energy is expended in healing the wound, and uniting the 

 pieces. If there is a large enough quantity left over, or already 

 in the pieces, hydranths develop at once at the two oral ends, but 

 if there is not a large enough amount present, one end is delayed 

 until the hydranth has been completed. This hypothesis may 

 serve to explain the hastening of the aboral hydranth after one has 

 been formed or is about to form in that region. If the hydranth 

 has formed there may be energy left over, if it is about to develop 

 there is a large amount of energy present. Under normal condi- 

 tions some stems contain more energy, or vitality. The preceding 

 tables show that from the two original components a large number 

 of hydranths may develop as many as eight, while from others only 

 one or sometimes none, appear. The conditions of the experiment 

 are apparently the same; the results can be explained in no other 

 way than that one individual possesses more energy than another. 

 I do not believe that there is any one material whose presence 

 modifies the result, it is the state of all the materials at the time 

 of the operation. 



3 GRAFTING A SHORT DISTAL PIECE ON THE BASAL END OF THE 



SAME STEM 



In an earlier paper ('oo) I described a series of experiments in 

 which a short distal piece of the stem w^as grafted in a reverse 

 direction, on the proximal or aboral end of a long piece. The 

 results which I obtained from a small number of experiments, 

 seemed to indicate that the long piece influenced the rate of develop- 

 ment of a new hydranth on the short piece, for the tentacle ridges 

 on the short piece did not appear until after the hydranths had 



