﻿CATALYSIS. 135 



Some alkaloids also have a similar "poisoning" effect on the decomposi- 

 tion of oxalic acid in the presence of uranium salts in the sunlight. 



Experiment IS. — 



(a) 4 grams oxalic acid. 



1 gram uranium acetate. 

 100 cubic centimeters water. 



(b) Same as (a) but with 0.1 gram of brucin added. Measure- 



ments in cubic centimeters. 



Time. («) (b) 



8.08 to 9.10 



47 



30 



10.22 to 10.45 



48 



29 



10.48 to 11.05 



52 



35 



11.08 to 11.25 



54 



29 



11.28 to 11.42 



50 



29 



11.44 to 12.00 



48 



20 



2.55 to 3.25 



54 



32 



3.30 to 4.00 



50 



25 



Brucin oxalate separates as white, crystalline needles when brucin is added 

 to the solution, so that the concentration of the alkaloid was less than was 

 represented by the amount added. 



Experiment 1J(. — The same solution as in experiment 13, excepting that quinine 

 was substituted for brucin in (b) . Quantities in cubic centimeters. 



Time. («) (6) 



8.15 to 9.20 



71 



27 



9.24 to 9.50 



76 



21 



9.53 to 10.20 



77 



20 



10.23 to 10.45 



68 



18 



10.48 to 11.10 



75 



20 



Experiment 15. — In this experiment 1 gram atropin was substituted for brucin 

 and a third solution (c) had added to it 0.2 gram cinchonin. Quantities in cubic 

 centimeters. 



Time. («0 (&) (c) 



a. m. 



11.25 to 12.00 



81 



20 



13 



p. m. 



2.20 to 3.50 



108 



40 



14 



a. m. 



10.40 to 11.20 



84 



34 



12 



p. m. 



1.00 to 1.40 



78 



34 



12 



a. m. 



8.00 to 8.45 



72 



30 



10 





8.50 to 9.30 



81 



40 



12 





9.40 to 10.15 



82 



33 



8 





11.25 to 12.00 



80 



33 



7 



Experiment 16. — (a) Standard solution, (b) With 0.1 gram morphine, (e) 

 With 0.1 gram strychnine. Quantities in cubic centimeters. 



Time. (a) (b) (c) 



p. m. 1.15 to 1.37 51 32 32 



a.m. 8.30 to 9.30 102 27 34 



9.33 to 10.10 103 38 40 



