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



569 



inverted without disturbance of the contents was considered as 

 the time of clotting. Since frequent movement of the test-tubes 

 tended to prevent the formation of a solid clot when the time of 

 clotting was prolonged, those experiments in which solid clots 

 were not formed have been rejected. All these experiments 

 have been repeated, some of them many times. 



The effect of alkali upon clotting.— Most of the experimental 

 work was performed with soda, the other alkalies being used only 

 as controls. When varying quantities of soda were added to 

 milk, results were obtained of which those recorded in Table i. 

 were typical. 



Table i. 

 Acidity of milk, 16-8°. 



Tube. 



Milk. 



/oNaOH. 



Water. 



Rennet. 



Result. 



1 



5 c.c. 



— 



Ice. 



0-15 c.c. 



Clotting in 37 min. 



2 





0-1 c.c. 



0-9 c.c. 





62 „ 



3 







0-2 c.c. 



0-8 c.c. 





137 „ 



4 







0-3 c.c. 



- 7 c-c. 





398 ,, 



5 



, 





0-4 c.c. 



0-6 c.c. 





No clotting. 



6 







0-5 c.c. 



0*5 c.c. 







/ 







0-6 c.c. 



0-4 c.c, 







8 



' 





- 7 c.c. 



0/3 c.c. 





?» 



From Table i. it will be seen that while 0-8 cc. —NaOH at 

 least was required to neutralise the milk, the addition of - 4 cc. 

 y^-NaOH sufficed to prevent clotting. Less quantities than 

 04 cc. y^NaOH also markedly delayed the onset of the change. 

 This milk therefore, though acid to litmus and phenolphthalein, 

 does not clot with rennin even after many hours. 



If the amount of rennet was increased, analogous results which 

 are tabulated in Table ii. were obtained. 



It is seen that while the greater quantity of rennet hastened 

 the time of clotting when the amount of soda was small, the addi- 

 tion of 0-4 c.c. y^NaOH to 5 c.c. milk prevented clotting. The 

 quantity of soda that was sufficient to prevent clotting in samples 

 44 



