BEHAVIOR AND FUNCTIONS OF THE NUCLEUS 3OI 



nellar bands can unite, oral parts may migrate together, and that 

 there is a fair amount of reorienting and mending of stripe patches 

 in minced stentors in the absence of the nucleus (Fig. 85A). Yet 

 we still need clear-cut tests and a precise definition of capabilities 

 for shape and form reconstitution in enucleated stentors. 



9. Functioning and re-formation of vacuole and holdfast 



in enucleates 



Balbiani (1889) found that the contractile vacuole of Stentor 

 functions without the presence of the nucleus. Its rate of pulsation 

 is even normal (Prowazek, 1904), as is the case in Amoeba 

 (Comandon and de Fonbrune, 1939b). A new contractile vacuole 

 appeared in enucleated posterior pieces of igneus (Balbiani, 1893) 

 and this was confirmed in coeruleus by Stevens (1903), Schwartz 

 (1935) and Tartar (1956c). The same has been known for Amoeba 

 since the work of Hofer (1890). As Balbiani remarked, the new 

 vacuole probably does not involve structural synthesis and may 

 arise merely by the enlargement of some feeding canal of the 

 existing contractile vacuole system. This is the more probable 

 since Schwartz observed new pulsating vacuoles in enucleated 

 stentors 3 minutes after the older ones had been removed. 



In enucleated stentors the old holdfast is quite capable of 

 functioning in reattachment (Stevens, 1903). It can also be 

 re-formed in the absence of the nucleus, as attested by firm 

 reattachment by a holdfast of coeruleus from which both tail-pole 

 and nucleus have been removed (Tartar, 1956c). This regeneration 

 is understandable on the basis that Httle if any synthesis is involved, 

 only a modification of existing parts. 



10. Behavior of enucleates 



First let us note that Schwartz (1935) observed vigorous cyclosis 

 of the endoplasm which continued nearly up to the point of death 

 in enucleated coeruleus. In regard to the *' external" behavior, 

 investigators were impressed from the start by the sustained 

 activity and normal swimming behavior of enucleated ciliates. 

 Similarly, it is well known that amcebas can continue forming 

 pseudopods in the absence of the nucleus. But in Stentor the 

 vigorous beating of thousands of body cilia and numerous huge 



