Factors m Regeneration 



325 



e all the lateral ends and the middle of the stem; 



/ the middle of the stem only; 



g all the lateral ends, then stem was cut into two equal parts; 



h not ligated — control stems. 



The rate of development in the different series varied consider- 

 ably. In the table the number regenerated for two and five days 

 after the first appearance of polyps is given. 



TABLE 8 



Polyps reg. on 



Oral ends 



66'^ 



87% 88% 



Lateral ends 54% 25% 52% 44% 



2days...<{ Basal ends 61% 75% 75% 100% 88% 100% 100% 



Total Average 



66'- 



Oral ends 123*^ 



Lateral ends 94^ 



5 days ■ ■ ■ \ Basal ends 102^ 



Average 106% 



70% 

 116 

 123 

 124 



62% 

 125 



IC30 



100 



94% 

 '55 

 155 



155 



70% 



66 



122 



94 



72% 



76 



137 



106 



118 

 118 



It will be observed, firstly, that hydranths are normally regen- 

 erated more readily at the oral rather than the basal ends of stems. 

 Secondly, with the same number of ligatures to the stem, the num- 

 ber of polyps regenerated depends on the location of the ligated 

 branch or branches; that is to say, tying a lateral end near the 

 basal region of the stem is less efficacious in stimulating basal 

 regeneration than a ligature on a lateral branch nearer the distal 

 end, which in turn is less efficient than a ligature at the apical 

 end. Thirdly, the total number of polyps produced or at least the 

 number of basal polyps, is in a general way proportional to the 

 number of ends ligated; the more ends ligated the greater the 

 total and basal regeneration. It should be recalled, however, that 

 ligating four lateral branches is less effective than one apical liga- 

 ture. Fourth, a ligature around the middle of a stem increases 

 the number produced at both oral and basal ends but not to the 



