116 



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



periods, the amount of change taking place was approximately proportional 

 to the time, the extent to which hydrolysis took place during the first hour 



Table II. 





Percentage of 



urea hydrolrsed 



Time. 













By 2 c.c. of Soja extract per 100 c.c. 



By 4'5 c.c. of Soja extract per 100 c.c. 



15 niins. 

 30 „ 



2 -0 

 3-8 



12 -6 



45 „ 



4-9 



16-3 



1 hour 



6-1 



21 -3 



1*5 „ 



7-9 



28 -4 



2-0 „ 



8-6 



35-0 



2 5 „ 



9-7 



40-9 



3-0 „ 



11-9 



46 -4 



4-0 „ 



13 -0 



56 -8 



4-5 „ 



13-8 



61 -3 



5-0 „ 



14 -3 



65 -4 



60 „ 



16 2 



73 -7 



6-5 „ 



17 -1 



77 "2 



24 -0 „ 



37 -1 



100 -o 



144 -0 „ 



52 -9 





Table III. — Hydrolysis of Urea in different Concentrations by the same 

 amount of Urease.* 



Time. 



Yolume of standard acid solution neutralised by 10 c.c. 

 samples of solution. 



M/5 urea 



solution. 



M urea solution. 



5M urea solution. ' 



5 mins. 



4 



95 



4-2 



c.c. 

 2-6 



10 „ 



7 



8 





4-0 



15 „ 



10 



35 



9-4 



5-2 



30 „ 



16 



9 



15 -55 



7-6 



45 „ 



22 



4 



20-85 





60 „ 



27 



1 



25 -75 



11 -9 



75 „ 



31 



25 







90 „ 

 2 hours 



35 



25 





15 -65 



39 



14 





19-1 



3 „ 







61 -8 



25 -4 



5 „ 







85 -35 



36-4 



7 „ 







108 -4 



46-2 j 



25 „ 

 49 „ 







196 -85 



93 -8 



1 



Volume of acid neutralised 

 by 10 c.c. on complete 

 hydrolysis 



39-5 | 197-5 987-5 



J 



* In these experiments, instead of boiling the solution after adding acid, the carbon dioxide 

 was expelled by means of a current of air, in order to avoid the error arising from the hydrolysis 

 of urea in concentrated solutions by the excess of acid. 



