440 



THE ACIDITY OF MILK, 



was 15 '5°. All these samples turned blue litmus paper red and 

 red litmus paper blue. Fluid litmus solution was turned red. 

 The samples were all without effect upon Congo red paper, which 

 detects free acid. The cows were tested on December 18th at a 

 farm on the Hunter River, 150 miles north of Sydney, at about 

 4.45 a.m. The detailed figures are given in Table i. 



Table i. 



No. 



Tempera- 



Acidity in 



Red litmus 



Blue litmus 



Congo red 





ture. 



degrees. 



paper. 



paper. 



paper. 



1 



320 C 



14 



blue 



red 



neutral 



2* 



26°C 



15 



?> 











2+ 



36°C 



135 



>• 











21 



30° C 



13 



>> 











2§ 



30°C 



14 



> J 











3 



36°C 



15 



J J 











4 



30°C 



15 



} > 











5 



31°C 



17 













6 



34°C 



19 



5 > 











7* 



27°C 



15-5 



J 1 











8* 



27°C 



15 



>> 











9* 



27°C 



16-5 



}» 











10* 



29-5°C 



16 



) > 











11* 



29*5°C 



16 



J > 











12* 



29-5°C 



16 



J > 











13+* 



28°C 



12 



5> 











13§* 



28°C 



14 



> 5 











14* 



28°C 



17 



> J 











Mixed milks* 



29°C 



14-5 



J) 







' 





A determination has been made of the rate at which the acidity 

 alters in a sample of milk. This milk was drawn into an open 

 vessel kept covered from dust though air freely entered. The 

 results are recorded in Table ii. 



* Cooled quickly. 



f First drawn milk. 



X Last drawn milk. 



§ Average sample from milking pail. 



