BY A. H. MOSELEY AND H. G. CHAPMAN. 



571 



If potash was substituted for soda, analogous results such as 

 those recorded in Table iv. were obtained. The addition of 

 0'5 c.c. jyKOH was sufficient to prevent clotting, though - 7 c.c. 



Acidity of milk, 14-6°, 

 5 c.c. milk in each tube. 



Table iv. 



0'15 c.c. rennet in each tube. 



Tube. 



T \KOH. 



Result. 



1 







Clotting in 27 min. 



2 



o-i 



30 ,, 



3 



0-2 



67 „ 



4 



0-3 



„ 12S „ 



5 



4 



150 ,, 



6 



05 



No clotting. 



7 



6 



,, 



S 



07 



" 



y^KOH, at least, was required to neutralise the milk. The 

 alkalies, soda and potash, in solution ionise freely, so that a large 

 number of hydroxyl ions are present in the solution. With the 

 carbonates, dissociation is less and the number of hydroxyl ions 

 is relatively much lower. Schields* has shown that in decinormal 



Table v. 

 Acidity of milk, 15°. 

 5 c.c. milk in each tube. 0"15 c.c. rennet in each tube. 



Tube. 



T V\a 2 C0 3 



Eesult. 



1 



— 



Clotting in 27 min. 



2 



0-1 c.c. 



28 ,, 



3 



02 c.c. 



66 ,, 



4 



0-3 c.c. 



82 ,, 



5 



0-4 c.c. 



223 ,, 



6 



0'5 c.c. 



No clotting. 



7 



0-6 c.c. 





S 



07 c.c. 



" 



sodium carbonate solution only about 3 % of the concentration 

 of hydroxyl ions in decinormal hydrate are found. Ammonia, 



Schields, Zeitsch. f. physik. Chem., Bd.xii. 



