REORGANIZATION lOI 



brought about extensive reorganizations in a stentor sample, but 

 this procedure was not easily reproducible. 



(c) Need for nuclear reorganization ? 



In one of his cytochemical studies, Weisz (1950b) reported that 

 in the chain macronucleus of coeruleus a gradient in affinity for 

 methyl green seems to develop in anticipating reorganizers and 

 pre-fissional animals, the posterior nodes staining less intensely. 

 In both cases, after clumping and renodulation the nuclear beads 

 stained uniformly. In this there is the implication that re- 

 organization might be to reinstate uniformity of composition of 

 the nucleus in animals vv^hich for some reason are not yet able to 

 divide. But Weisz did not say so explicitly, perhaps because he 

 found reorganizers in "all cycle stages", i.e., at any time during 

 the interfissional period. 



(d) For growth of the adoral band ? 



It will be recalled from the account of the reorganization process 

 that important new additions to the membranellar band and the 

 frontal field take place, while only the gullet and the border of the 

 oral pouch are obviously resorbed. Therefore a considerable 

 enlargement of the head should result. Schwartz (1935) carefully 

 counted the membranelles and found that approximately twice as 

 many are added as are resorbed. This suggested to him that re- 

 organization may be a periodic growth process serving in part for 

 the increase in the length of the membranellar band as well as 

 perhaps the enlargement of the mouthparts. Favoring this concep- 

 tion is the finding that if for any reason the primordium produces 

 too small a head, with a short membranellar band and limited 

 frontal field, reorganization soon occurs with resulting enlargement 

 of these parts (Tartar, 1958b). 



In at least one case, however, I found that when an extra head 

 was grafted to a stentor and this fused with the original to form 

 a supernormal number of membranelles, reorganization never- 

 theless occurred. There are other arguments against the growth 

 hypothesis. When there are repeated reorganizations the membran- 

 ellar band does not become of exaggerated length. We are obliged 

 to assume that the immediate increase results in a compensatory 

 resorption of membranelles in some part of the band. Only in 



