570 TROPICAL HYGIENE, SANITATION, ETC. 



A rose-red colour is positive for cane sugar. 



Anv deposit should be examined with a microscope for starch, pus, 

 ind dirt which can be readily detected. 



Milk with a specific gravity below i"028 contains an exceptional 

 amount of cream or has been adulterated. It is normally i "028-1 "035. 

 If there is less than 3 per cent, of fat it has usually been adulterated. 



Bacterially milk should be examined for the tubercle bacillus and 

 the cholera vibrio. The tubercle bacillus is rarely found in India. 



For T.B. 



Centrifuge a small quantity of milk. 



Take the deposited portion and inoculate two guinea-pigs. 



If T.B. is present the animals will show it in three to six weeks. 



The tuberculin reaction is useful for cows. 



For cholera vibrio. 



Isolate in Durham's peptone solution with i c.c. of milk and plate 

 out. Identifv the organisms. For more details, see special section 

 on Laboratory Hints. 



Milk may be manipulated as follows : — 



(New South Wales Report of the Government Bureau, 1909). 

 (i) Mechanical contrivances. 

 Centrifugalization . 

 Filtering. 



(2) The application of heat. 



Sterilization. 

 Boiling. 

 Pasteurization. 

 Concentration. 

 Desiccation. 



Thermophore treatment, similar to thermos treatment, to 

 prevent excessive growth of bacteria by continuous warming. 



(3) The application of cold. 



Freezing. 

 Chilling. 

 Cooling. 



(4) The addition of antiseptics. 



Sodium bicarbonate. 



Boric acid, borax or mixtures. 



Formalin. 



Salicylic acid. 



Peroxide of hydrogen. 



(5) The inducement of alcoholic fermentation. 



Koumiss. 

 Kepiiir, &c. 



