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GABRIELE KASS-SIMON 



change in TRF's and the second set of buds seem to indicate that a change of some 

 sort had occurred in the budding région itself. 



The delay in Time of Tentacle DirTerentiation for week-old budding animais 

 is neither so consistent nor so short, indicating that perhaps in thèse animais, the 

 région surrounding the site of the bud was more affected than in day-old animais. 

 It is perhaps interesting to speculate that thèse animais being older and having 

 been very well fed are less able to respond to an other-than-bud-producing stimulus 

 in the budding région once this région has been primed for budding. And it is 

 here put forth that food stimulâtes normal growth of the animal until a certain 

 maximum is reached which causes a switch-over at the budding zone into a 

 budding condition; which condition, while the animal is budding (and perhaps 

 shortly before and after), renders this zone incapable of reacting to a régénération 

 stimulus. This might explain why only the régénération in the actual budding area 

 is negatively affected by the présence of a bud and why older budding animais 

 take a longer time to begin regenerating than do younger ones: Presumably, then 

 they are more likely to retain their budding condition (in the budding zone) — a 

 delay in the switch back to the normal, i.e. régénération responsive, condition 

 being postulated. This switch-over is thought to occur exclusively in the budding 

 area, essentially independent in its effects on other régions. This idea is supported 

 by experiments performed on the budding région by Diehl (Dieiil and Burnett, 

 1964). And the performance of buds is thought to be its conséquence rather than 

 its cause; the switch-over would be due to a large quantity of food. 



V. FEEDING AND REGENERATION 

 (a) Introduction 



The question of the effect of différences in feeding on the time at which 

 tentacles and basai plates first appear and the effect of excessive feeding on the 

 régénération performance is dealt with in this section. 



In a first experiment, standard animais, modified with respect to feeding, are 

 given specified amounts of food 24 hours before transection; their régénération is 

 evaluated according to the usual criteria. Because day-old, i.e. standard, animais 

 were thought to contain nutritional reserves in conséquence of their récent status 

 as buds, week-old cloned animais were selected in a second experiment and sub- 

 jected to varying conditions of feeding and in turn compared to day-old animais 

 under comparable feeding conditions. The results of the two sets of experiments 

 are not in complète agreement and the question of possible unknown variables 

 remains a problem for further investigation. 



