CANE SUGAR DETECTION. 169 



calculate the solids not fat (a) from the specific gravity and per- 

 centage of fat, (b) from the percentage of ash by multiplying by 

 12, or the aldehyde figure by 0-44. The cane sugar will be repre- 

 sented by a b. If the original milk is available the ratio 

 between the solids not fat and the aldehyde figure may be 

 determined, and this figure substituted for 0-44. 



Cotton's Method of Detecting Cane Sugar. Cotton gives 

 the following test for cane sugar in milk : 10 c.c. of the milk 

 are mixed with 0-5 gramme of powdered ammonium molybdate 

 and 10 c.c. of dilute hydrochloric acid (1 : 10). In a second tube 

 10 c.c. of milk of known purity, or 10 c.c. of a 6 per cent, solu- 

 tion of lactose, are treated similarly. The two tubes are placed 

 in a water-bath and the temperature raised gradually. At 

 about 80 C. the milk, if adulterated with saccharose, assumes 

 an intense blue colour, whilst the genuine milk, or solution of 

 lactose, remains practically unaltered. On boiling, these latter 

 also turn blue, but to a less extent than the adulterated milk. 



This test will detect 0-1 per cent, of cane sugar, but if this 

 substance be added to milk, larger quantities are almost invari- 

 ably added. 



De Koningh modifies Cotton's test by adding 2 c.c. of a satu- 

 rated solution of ammonium molybdate and 8 c.c. of acid (1:8) 

 to 10 c.c. of milk. The test-tube is gradually heated to 80 C. 

 (not higher), and kept for five minutes at this temperature. 



Rothenfusser tests for cane sugar, by precipitating the lactose, 

 proteins, and fat by adding 10 c.c. of freshly prepared ammoniacal 

 lead acetate solution to 10 c.c. of milk (430 grammes of neutral 

 lead acetate and 130 grammes of litharge are boiled for half- 

 an-hour with 500 c.c. of water ; after cooling the decanted 

 liquid is diluted to specific gravity 1-15 ; 2 volumes of this are 

 mixed with 1 volume of 0-959 ammonia). To 4 c.c. of the'filtrate 

 8 c.c. of diphenylamine reagent are added (20 c.c. of a 5 per cent, 

 solution of diphenylamine ' in 95 per cent, alcohol + 60 c.c. 

 glacial acetate acid + 60 c.c. hydrochloric acid, specific gravity 

 1*17 and 60 c.c. of water) and heated in the water -bath for ten 

 minutes. A blue colour indicates cane sugar. 



W. H. Anderson has recommended Cayaux's test for cane 

 sugar ; this consists in adding to 15 c.c. of milk 1 c.c. of hydro- 

 chloric acid and 0-1 gramme of resorcinol. On boiling a red 

 colour is produced in the presence of cane sugar ; 0*2 per cent, 

 is detected by this test. 



Leffmann and later Gawalowsky employ the reaction with 

 sesame oil and hydrochloric acid to test for cane sugar. 1 c.c. 

 each of sesame oil and hydrochloric acid are mixed with a little 

 of the filtrate produced by adding strong hydrochloric acid to 

 milk, and the mixture shaken actively for a few moments ; if 



