f6 LECTURES ON IMMUNITY 



where M denotes the quantity of milk (in cubic centi- 

 meters) present in the solution. 



Very complicated results were obtained on dilution with 

 0.9 per cent solution of sodium chloride, as is seen from 

 the following table, in which M and R respectively desig- 

 nate the number of cubic centimeters of milk and rennet 

 respectively present in 10 c.c. of the solution. (The 

 rennet contained calcium salts.) The rest (10 M R ) 

 is the quantity of salt solution added. The tabulated 

 figures give the time of coagulation in seconds. 



R = 2 1.5 i 0.9 0.8 0.7 0.6 0.5 0.4 0.3 



M= 1.25 c.c. 34 9 12 14.5 19 33 50 107 810 



3 c.c. 46 10 11.5 '14 18 24 32 45 78 



8 c.c. 8 9 ii 12 14 16 19 23 29 42 



If R = 0.8 or 0.9 c.c., the time of coagulation is nearly 

 independent of the dilution of the milk ; at lower concen- 

 trations of R the time increases with dilution, at higher 

 concentrations of R the opposite is true. 



According to the views of Saw] alow the coagulation of 

 milk is only a special case of digestion in which one of the 

 products coagulates. This agrees very well with experi- 

 ments at low temperatures first executed by Morgenroth, 1 

 and then repeated by Fuld. They prepared mixtures of 

 rennet and milk, which were held at low temperatures. 

 Then no coagulation occurred, but the digestion process did 

 occur. After these mixtures had been held for some time 

 at the low temperature and were then heated to 20 or 

 more, they coagulated instantaneously. 



1 Morgenroth : Archives Internationales de pharmarcodynamie, 7. 265 

 (1900). 



