256 THE BIOLOGY OF STENTOR 



I to 4 days, with complete regeneration occurring on return to 

 normal medium. Regeneration was sometimes merely delayed, 

 astomatous, or blocked in development at stage 4, which is just 

 the stage at which the primordium becomes susceptible to shedding. 

 Abortive fissions were noted, as well as distortions of body 

 striping. In successive reorganizations, LiCl prevented the resorp- 

 tion of the old organelles, with the result that there was a stacking- 

 up of several sets of feeding organelles, as shown. Perhaps most 

 provocative of all was that the stentors became very broad, as 

 if multiplication of lateral striping had been stimulated much 

 beyond the normal bounds, and in fact some of these animals 

 spontaneously converted into doublets, as illustrated. 



The only previous test of the eifect of LiCl on ciliates to my 

 knowledge was that of Faure-Fremiet (with J. Ducornet, 1949) 

 who found that this agent produced microstomatous forms in 

 Tetrahymena. This he attributed to inhibition of the multiplication 

 of cilia, yet it appears that, in Stentor, broadening of the cell is 

 accompanied by increase of kinetics and therefore considerable 

 multiplication of cilia and related structures. 



It is well known that lithium has special eifects on developing 

 eggs, producing in general a vegetalization or depressing a gradient 

 whose maximum is at the animal pole (see Gustafson, 1954). The 

 precise nature of this effect is not known. It may be that lithium 

 alters the hydration of proteins, for it seems to produce a coarse- 

 ness of the cytoplasm in general and to cause proteins to become 

 fibrillar, coagulated, and stable. Raven (1949) states that lithium 

 seems to affect especially the density of the cortical cytoplasm in 

 the eggs of Limncea. Since the major morphogenetic events in 

 stentors are also located in the cortex of the cell, the effects may 

 be comparable and one might even regard suppression of differen- 

 tiation of the feeding organelles and concomitant broadening of 

 the lateral ectoplasm as a parallel of *' vegetalization ".At any rate 

 it is most interesting that lithium has unique effects upon Stentor, 

 as it does upon embryos. 



13. Inhibition of growth by X-ray, and other effects 



Kimball (1958) subjected coeruleus to X-rays and found that 

 when irradiated animals were returned to culture medium fission 

 was much delayed. Although the stentors fed and formed food 



