30 BULLETIN 202, U. S. DEPARTMENT OF AGRICULTURE. 



Table 24. — Alcohol titrations of milk inoculated with pure cultures of bacteria. 













Alcohol titra- 













tion. 



Experi- 

 ment. 



Culture. 



Age of 



milk 



culture. 



Acid- 

 ity. 



Bacteria 

 per cubic 

 centimeter. 







90 per 

 cent to 



80 per 

 cent to 













2c.c. of 



2c.c.of 













milk. 



milk. 



1 



Lactic-acid bac- 



Hours. 







c. c. 



c. c. 





teria 





 2 

 3 



1.95 

 1.95 

 1.90 



64,000 



3.08 

 2.86 

 3.14 



8.88 

 9.13 

 9.42 





131,666 







4 



1.95 



120,000 



2.60 



9.52 







5 



1.95 



361,000 



3.05 



9.40 







6 



2.05 



736,000 



3.05 



8.85 







6J 



2.07 



1,660,000 



1.85 



7.08 





Rennet-forming 















bacteria 





 2 



1.95 

 1.90 





3.12 



3.03 



9.02 

 9.52 



1,600 







3 



1.95 



70,000 



2.50 



9.48 







4 



2.03 



230, 000 



2.44 



9.83 







5 



2.04 



2,850,000 



3.20 



9.90 







6 



2.04 



9,300,000 



2.80 



8.12 







61 



2.07 



11,100,000 



1.87 



6.18 



2 



Lactic-acid bac- 















teria 







2 



2.00 

 2.00 



25, 000 

 184,000 



3.33 



3.58 



12.55 

 13.82 









3 



2.08 



475,000 



3.52 



11.18 



' 





4 



2.04 



1,710,000 



3.73 



9.85 







5 



2.18 



4,900,000 



2.00 



7.32 







6 



2.26 



8,400,000 



2.00 



5.50 







7 



2.33 



22,500,000 



1.06 



1.79 





Rennet-forming 















bacteria 







2.00 



6,100 



3.32 



13.95 







2 



2.00 



51,500 



3.40 



13.36 







3 



2.00 



234,000 



3.98 



10.52 







4 



2.00 



1,325,000 



3.57 



9.35 







5 



2.00 



1,300,000 



1.56 



8.98 







6 



2.04 



13,000,000 



1.25 



2.93 







7 



2.20 



21,800,000 



0.83 



1.21 



THE ALIZAROL TEST. 



When the alcohol has alizarin added to it to act as an indicator 

 for the acidity the alcohol test is known as the alizarol test. This 

 name was given to the test by Morres (21). The use of alizarin as 

 an indicator for the acidity of milk has been known for a long time, 

 but Morres (19) was probably the first to combine the alcohol and 

 alizarin test. He pointed out that the alcohol test was of more value 

 than the litmus test and that the combination with alizarin was 

 better than the combination of litmus and alcohol. Morres (20) 

 used a 68 per cent alcohol with 1.2 grams of fresh alizarin paste, or 

 0.4 gram of dry alizarin to 1,000 c. c. of alcohol. Two cubic centi- 

 meters of this alizarin- alcohol solution are mixed with 2 c. c. of milk, 

 the same as in the alcohol test. This author found that from the 

 coagulation by alcohol and the color of the alizarin it was possible 

 to obtain a picture of the condition of the milk. According to 

 Morres (20) the alizarol test shows the following conditions: 



1. Lilac -red color. (Milk titrated 7° acid.) 



(a) With no coagulation. The milk should keep sweet more than 6 hours. 



(b) With fine flaky coagulation. The beginning of rennet production is shown 



here. 



(c) With heavy flocculent coagulation. This indicates advanced rennet forma- 



tion. 



