THE CARBOHYDRATES. 17 



in weight gives the amount of dextrose in 10 cc. ; so that 

 the amount in 1 cc. is got at once = p. 



(g.) Calculate the specific rotatory power by the above 

 formula. It is about + 53. 



For practice, begin with a solution of dextrose containing 

 11 grms. per 100 cc. of water. Make several readings of the 

 amount of rotation, and take the mean. 



Example.- In this case, the mean of the readings was 11-6 



11-6 



Repeat the process with a 4 and 2 per cent, solution. It is 

 necessary to be able to read to 2 minutes, but considerable prac- 

 tice is required to enable one to detect when the two halves of 

 the field have exactly the same intensity. 



Test the rotatory power of corresponding solutions of cane- 

 sugar, and any other sugar you please. 



Test also the rotatory power of a proteid solution. 



The following indicate the S.R. for yellow light : 



Proteids. Egg-albumin - 35 '5; serum-albumin - 56; syn- 

 tonin - 72 ; alkali-albumin prepared from serum-albumin - 86, 

 when prepared from egg-albumin 47. 



Carbohydrates. Glucose + 56; maltose + 150; lactose 

 + 52-5. 



NEUTRAL FATS. 

 13. Reactions. 



(a.) Use almond oil or lard, and observe that fat is soluble 

 in ether, chloroform, and hot alcohol. 



(6). To almond oil add caustic soda, and boil = saponifi- 

 cation. 



(c.) Shake oil containing a fatty acid e.g., De Jongh's 

 cod-liver oil, with a few drops of a dilute solution of sodic 

 carbonate. The whole mass becomes white = emulsion. 

 Examine it microscopically, and compare it with milk, 

 which is a typical emulsion. 



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