PETERS. — METABOLISM AND DIVISION IN PROTOZOA. 509 



bore was placed in the graduate for the purpose of withdrawing por- 

 tions of the liquid. Its inner end was bent upward, so that the pro- 

 cess would not disturb the Stentors lying below. Its outer end was 

 closed by a piece of rubber tubing with a clamp placed upon it. Por- 

 tions were withdrawn for chemical examination according to the follow- 

 ing schedule : 



Dec. 13. 1.49 p. M. — Placed Stentor in CaCl 2 solution. 



1.53 p. m. — Withdrew about 35 cc. Portion No. 1. 



2.18 p.m.— " " 35 " " 2. 



2.50 p.m.— " " 35 " " 3. 



Dec. 15. 11.00a.m.— " " 45 " " 4. 



The several portions withdrawn were immediately estimated for chlo- 

 rine by argentic nitrate with neutral potassic chromate for indicator. 



The amount of acid or alkali necessary to produce reaction with 

 methyl orange and phenolthalein was also found. The estimations with 

 argentic nitrate gave the following result : 



Chlorine. 



Portion. Time (approximate) 



1 5 min. 5 cc. required 10.95 cc. of .01 n. AgN0 3 . 



2 30 min. 5 cc. required 10.55 cc. of .01 n. AgN0 3 . 



3 1 hr. 5 cc. required 10. GO cc. of .01 n. AgN0 3 . 



4 2 da. 5 cc. required 11.80 cc. of .01 n. AgN0 3 . 



These determinations were made by means of a 20 cc. burette grad- 

 uated to .05 cc. The sensitiveness and accuracy of the process ex- 

 ceeded this amount of the argentic nitrate solution. The estimations for 

 acidity and alkalinity were as follows : 



Portion. Time. 



. j 5 cc. required .15 cc. of .01 n. HC1, methyl orange. 



( 5 cc. required .05 cc. of .01 n. NaOH, phenolthalein. 

 • ( ^ cc ' re( l un ' e d -15 cc. of .01 n. HC1, methyl orange. 

 ' ( 5 cc. required .05 cc. of .01 n. NaOH, phenolthalein. 



3 1 hr. 5 cc. required .15 cc. of .01 n. HC1, methyl orange. 



4 2 da. 5 cc. required .18 cc. of .01 n. HC1, methyl orauge. 



The result shows that within a period of one hour immediately follow- 

 ing the transfer of Stentors the concentration of chlorine in the medium 

 decreases. If the Stentors did not change their volume, the result would 

 demonstrate the penetration of chlorine into the cell. In that case, con- 

 ditions being isotonic, some other ion would pass outward into the 



