ANALYSIS OF STENTOR 



251 



He found that pigment shedding was the immediate response of 

 stentors transferred to certain solutions and that animals could 

 even later divide in media which caused shedding. The colored 

 slough he described as of gelatinous consistency, a homogeneous 

 halo without granules. Such sloughing was produced in KCl, 

 NaCl, KNO3, Na2S04, (NH4)2S04, Na2HP04, NaOH, HCl, 

 lactose, and chloroform but no shedding occurred in CaCl2, 

 Ca(0H)2, CaS04, or MgS04. Hence monovalent cations which 

 are the ones producing reversal of ciliary beating also elicit the 

 sloughing response, but bivalent cations do not. The effect is 

 obviously not osmotic since lactose and chloroform gave a similar 

 result and CaCU protected the animals against the shedding effects 

 of Na2S04, although the osmotic pressure was correspondingly 

 increased. In chloroform and Na2S04 some layers of the pellicle 

 apparently were also shed as a " heavy coat ". Peters suggested 

 that the pigment is a protein which is dissolved by certain salts. 



We have just noted that Daniel (1909) obtained shedding of 

 pigment in alcohols and NaOH but not in glycerine. 



Peters' study was confirmed and extended in some of my own 

 investigations (Tartar, 1957a). I also found that monovalent 

 cations produced pigment shedding, while calcium and magnesium 

 salts did not. The most vigorous shedding occurred in NaHCOa, 

 NH4CI, and LiCl. In strychnine there was a violent shattering 



\^ N 



Fig. 70. 



A. Shedding of pellicular layer and some pigment granules 



in <S. coeruleus in i % ammonium chloride. 



B. Casting off the membranellar band in 2% urea, a: Band 

 shed following fimbriation of membranelles, with last part to go 

 being the gullet lining, b: Neat removal of peristome in proper 

 treatment, with lateral and frontal stripe structures remaining 

 unaffected, c: Extended treatment produces two fronts of 

 disintegration, but if stopped (d) middle piece separates, survives, 



and regenerates. (After Tartar, 1957a.) 



