ANALYSIS OF STENTOR 243 



common fixing agents. From this fact together with the general 

 similarity between the response of stentors and nerve preparations 

 to the drugs and antagonists which he tested, Neresheimer con- 

 cluded that the effects were not on the myonemes themselves but 

 on the " neurophanes " which were therefore of a neuroid 

 character. Dierks was, of course, of the same opinion with regard 

 to his '' neuroids " and he found that coeruleus became insensitive 

 to touch in KCl, while CaCL increased contraction and was 

 antagonistic to the action of potassium ; for animals made insensi- 

 tive in the potassium salt regained their irritability when calcium 

 chloride was added. Relaxed stentors still contracted when fixed 

 with Flemming's solution. But contraction of the cell in strongly 

 coagulating solutions can scarcely be taken as demonstrating that 

 the myonemes were not directly affected and the impression 

 remains that much more sophisticated studies will be needed to 

 demonstrate similarities and differences between the responses of 

 stentors and typical nerve-muscle preparations. 



Merton (1932, 1935) also attempted to treat stentors so that they 

 could be fixed and stained in the extended form. Anticipating 

 Dierks, he found that KCl gives a partial anaesthesia of the 

 myonemes. In dilute Ringer's solution, stentors became out- 

 stretched but their irritability was increased. Metal salts of iron 

 and copper were said to produce differential contractions of the 

 cell and from his description it appears that the anterior end of the 

 stentor contracted while the tail-pole remained extended. Copper 

 sulphate produced a hardening of the cortex which therefore 

 antagonized the contraction of the myonemes and left stentors in 

 a semi-extended state. Fairly well extended preparations were 

 made by relaxing stentors for 2 to 3 hours in Ringer's solution 

 diluted 1:3, then applying weak copper acetate to harden the 

 surface, following this treatment with fixation. 



Dierks (1926b) confirmed that a 0-5% solution of KCl renders 

 stentors insensitive to touch. Conversely, CaCl2 increased contrac- 

 tion and was antagonistic to the action of potassium, animals 

 regaining their irritability when calcium was added. A 0-04% 

 solution of Na2S04 paralyzed both cilia and myonemes, but stentors 

 relaxed in this way or with KCl still contracted on fixing. 



