226 Milk Inspection. 



2. Microscopical test of the sediment and examina- 



tion as to the presence of parenchyma cells and 

 diplococci, streptococci of the short and long 

 forms, particularly the animal types or the 

 pyogenes or tuberculosis bacillus. 



3. If necessary the catalase test or examination for 



amylase. 



(c) Samples from individual quarters: 



1. Trommsdorff or sediment tests. 



2. Microscopy and, if necessary, inoculation. 



3. Catalase or amylase test. 



In examinations for milk defects, the following tests are 

 recommended : 



1. Tests with the senses. 



2. Shaking test (soapy milk). 



3. Eeductase test (frequently the reduction appears very 



slowly, for instance, with tallowy and soapy milk). 



4. Acid tests. 



5. Historical consideration of the conditions of stables, 



pasturage, litter, feed and water, preparation of milk. 



6. Fermentation test. 



7. Cultivation of bacteria from the milk, feed, pastures, etc., 



at temperatures at which the defects in the milk 

 appeared. 



8. Examination of cultures in sterilized milk. 



(a) Pure cultures, 



(b) Special mixtures of colonies. 



The veterinarian should also be able to conduct the routine 

 examination methods usually conducted in the milk laboratory 

 and the preliminary chemical tests for adulteration, provided food 

 chemists are not available in such localities. It would lead too 

 far to mention at this time all the methods which may be applied 

 in suspected adulterations. Only a few methods will be described, 

 particularly those which are employed at the official milk labora- 

 tory in Munich. 



Determination of the specific gravity of milk. It is best to 

 test the milk for its specific gravity after heating it to 15 C. or 

 in the neighborhood of this temperature. The milk is shaken 

 up and it is advisable to make the test in suspended cylinders with 

 the aid of an aerometer and a thermometer. It is not advisable 

 to use aerometers into which thermometers are fused. The lac- 

 todensimeter used for milk must be officially tested. The specific 

 gravity of milk varies in accordance with its contents in dis- 

 solved, suspended and emulsified ingredients. 



The lactodensimeter is slowly immersed in the milk and 

 should not touch the walls of the cylinder. After the instrument 

 has come to a rest, the place at which the level of the fluid touches 



