THE ALCOHOL TEST IN RELATION TO MILK. 31 



2. Pale-red color. (Milk titrated. 8° acid.) 



(a) With no coagulation or only very fine coagulation. This shows the beginning 



of lactic-acid fermentation. 

 (6) With flaky coagulation. Acid and rennet fermentation is indicated, 

 (c) With coagulation with very thick flakes. A mixed fermentation is indicated 



with advanced rennet and the beginning of acid fermentation. 



3. Brownish-red color. (Milk titrated 9° acid.) 



(a) With coagulation with fine flakes. Well-advanced pure acid fermentation is 



indicated. 



(b) With coagulation with thick flakes. A mixed fermentation with advanced 



rennet and strong acid fermentation is indicated. 



(c) With coagulation with very thick flakes. A very advanced rennet production 



and little less important acid fermentation is indicated. 



4. Reddish-brown color. (Milk titrates 10° acid.) 



(a) With flaky coagulation. Advanced pure acid fermentation is indicated. 



(b) With thick flaky coagulation. Advanced acid fermentation and the begin- 



ning of rennet production is indicated. 



(c) With very thick flaky coagulation. A proportional mixed fermentation 



which is well advanced is indicated. 



5. Brown color. (Milk titrates 11° acid.) 



(a) With thick flaky coagulation. Pure acid fermentation is indicated. Milk is 

 sour; to be detected by smell. 



(6) With veiy thick flaky coagulation. Some rennet production and well ad- 

 vanced acid fermentation is indicated. 



6. Yellowish-brown color. (Milk titrates 12° acid.) 



(a) With very thick flaky coagulation. Acid fermentation is indicated. Milk 

 tastes acid . 



7. Brownish-yellow color. (Milk titrates 14° acid.) 



(a) With very thick flaky coagulation. Sour taste is distinctly noticeable. 



8. Yellow color. (Milk titrates 20° acid.) 



(a) With very thick flaky coagulation. Pure acid fermentation is indicated. 

 Milk smells and tastes strongly acid and is near the normal coagulation 

 point. 



9. Violet color. (Milk titrates 7° acid.) 



No fermentation is indicated, but the milk is abnormal. 



It can not be disputed that a simple test which will picture con- 

 ditions in milk, as claimed by Morres, would be of considerable value. 

 But will the alizarol test indicate all that Morres claims ? Devarda 

 and Weich (6) in 1913, after working with this test, decided that it 

 had no value over the alcohol test. In a later paper Devarda (7) 

 draws conclusions as follows : 



1. For market control the alcohol test is satisfactory for the determination of the 

 quality of milk. 



2. The assertion of Morres that the alizarol test can show a pure rennet and mixed 

 fermentation is without scientific or practical significance. 



3. In a pure lactic fermentation the alizarol test stands close to the acidity in its 

 color relation, but for the determination of the keeping quality of milk it is of slight 

 significance. 



4. The diagnostic value of the alizarol test is limited to an empirical test for milk, 

 principally as to its suitability for cheese making which was already employed by 

 Eugling in 1882. 



Thoni (30), in a study of the milk supply of Berne, found that 12 

 of 85 samples examined were more or less abnormal, according to 



