572 CONTRIBUTION TO OUR KNOWLEDGE OF THE ACTION OF RENIN, 



also, is only slightly dissociated in solution (about •—■ of sodium 

 hydrate). Series of experiments with sodium carbonate and 

 ammonia are tabulated in Tables v. and vi. With sodium car- 

 bonate, while - 75 c.c. —NaOH was required to render 5 c.c. milk 

 neutral, the addition of - 5 c.c. -~Na„C0 3 prevented clotting. 

 With ammonia, 06 c.c. ~-NH 3 was required to prevent clotting, 



Table vi. 

 Acidity of milk, 14 - 6°. 

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



Tubes. 



N NTT 



Eesult. 



1 







Clotting in 27 min. 



2 



0-1 c.c. 



34 „ 



3 



0-2 c.c. 



68 ,, 



4 



0-3 c.c. 



134 „ 



5 



0-4 c.c. 



138 „ 



6 



0-5 c.c. 



210 ,, 



7 



0-6 c.c. 



No clotting 



8 



07 c.c. 



>> 



while a little more than 0"7c.c. ~-NH 3 was necessary to produce 

 neutrality of reaction. 



The effect of alkali and soluble lime salt. — It is well known that 

 removal of the soluble calcium salts from milk prevents the 

 formation of a clot by rennin, though this removal does not 

 interfere with the conversion of caseinogen into casein; and, 

 further, the addition of small amounts of soluble lime salts 

 hastens the clotting by rennin. If a soluble lime salt was added 

 at the same time as the soda, clotting occurred rapidly. In the 

 series recorded in Table vii., 1 c.c. ^CaCl 2 was added to a series 

 otherwise similar to that recorded in Table i. From Table vii., it 

 is seen that the speed of clotting was rapid whatever amount of 

 soda was present. While the addition of calcium chloride at the 

 same time as soda sufficed to produce clotting, yet the addition 

 of calcium chloride after soda, rennet, and milk had been in 

 contact many minutes was without effect in causing clotting.. 



