122 Prof. H. E. Armstrong and Mr. E. Horton. [Jan. 26, 



Table VII. — Hydrolysis of Urea in the presence of Carbon Dioxide. 





1st experiment. 



2nd experiment. 





Percentage of ure 



a hydrolysed in 



Percentage of ure 



a hydrolysed in 



Time. 





















• 



Aqueous solution. 



Carbonic acid 

 solution. 



A 1 « 



Aqueous solution. 



Carbonic acid 

 solution. 



mins 











- 



12 -3 



18 -2 



11-7 



19 -9 



10 



19-5 



32 -3 



19 -0 



32 5 



15 



j 26-6 





25 -5 



44 -0 



20 





54 -3 





54 -0 



30 





73-4 



41 -8 



74-0 



40 



48 -9 







91 -9 



45 





95 -5 



54 -0 





60 



65 -3 



95 -7 



65-5 



99 -0 



75 



76 -0 



96 -5 



75 -9 





90 



84 -5 



98 -0 



85 -4 



99 -6 



105 





98 -5 







120 



98 -5 





98 -5 





of the gas through the solution while it was heated in the incubator in 

 proximity to the unheated solution.* 



A similar effect is produced by the " amino-acid " glycine — thus the 

 activity of a solution of the enzyme which produced 24 per cent, of 

 change was raised to 35'3 per cent, by adding sufficient glycine to make 

 it a 2N/5 solution of this substance. 



Influence of Salts and Non-electrolytes. — As ammonia salts hasten whilst 

 salts of the alkali metals retard the formation of urea from cyanate of 

 ammonia, it was important to contrast the effect produced by ammonium 



* Note added February 23.- — The following series of results obtained recently are of 

 interest as confirming those quoted in the communication, especially as the experiments 

 were carried out simultaneously and with the same sample of enzyme. The very rapid 

 rate of change in the presence of carbonic acid towards the close of the period of 

 hydrolysis is noteworthy. A very striking diagram is obtained by plotting graphs from 

 the figures given. 



Percentage of Urea Hydrolysed in M/5 Solutions when alone or in presence of l/10th 

 equivalent of ammonic carbonate or l/10th equivalent of ammonia, and in a solution 

 saturated with carbon dioxide. 



