^^^ Florence Peebles 



2 TWO LONG PIECES GRAFTED TOGETHER BY THEIR ORAL ENDS 



Experiment I. Two pieces of stem, each measuring about 3 

 cm., were grafted together by their oral ends (Fig. 11). The 

 grafts were left undisturbed for twenty-four hours, then the double 

 piece was cut at two levels (Fig. 11, J and 2) so that each compo- 

 nent was halved. The distal halves of each were united by their 

 oral ends forming the piece B while the proximal halves of each 

 (J and C) had their oral ends exposed by a fresh cut, their aboral 

 ends having a start of twenty-four hours. New oral hydranths 

 formed on J and C at practically the same time, the aboral usually 

 preceding the oral by a few hours, or forming simultaneously with 

 it. The piece B developed a very small proportion of hydranths 

 at its free aboral ends, but in nearly every graft double heads 

 formed, one on the oral end of each component; these emerged and 

 finally pulled apart. These oral hydranths were much slower 

 in developing than the oral hydranths on the free ends of y^ and C. 

 When the second operation followed a few hours after the first, 

 the percentage of hydranths formed at the line of union was greatly 

 reduced. The free aboral ends rarely developed hydranths at the 

 same time, one usually preceded the other by six or eight hours. 

 The oral hydranths on A and C in this experiment formed before 

 the aboral hydranths with very few exceptions. 



Experiment 2. In a second series of experiments in which the 

 two components were grafted together by their oral ends (Fig. 

 12), the level of the first cut was changed so that^ consisted of the 

 major part of one component, while in B instead of the components 

 being equal in length, one was much longer than the other (Fig. 12, 

 A and B). A period of eighteen to twenty-four hours elapsed 

 between the first and second operations. Table 11 gives the 

 results from eighteen grafts. These practically represent the en- 

 tire series of experiments so that it is unnecessary to give other 

 tables. 



If we consider the rate of appearance of the hydranths we see 

 that the percentage of aboral hydranths is very large, and that 

 they appear before the oral hydranths of the same piece with few 

 exceptions. The number of hydranths on the oral end of the 



