102 Analysis of Feeding Materials [150-153 



in the same manner. Next digest with equally dilute caustic 

 alkali, and repeat the washing. This renders the texture of all 

 those seeds commonly met with in cattle foods, and the impu- 

 rities occurring with them, sufficiently transparent to be readily 

 recognised under the microscope. After washing the alkaline 

 liquid away, it is sometimes an advantage to wash the material 

 with dilute hydrochloric acid, which reduces the strong colour 

 produced by the alkali. 



Another method which produces the same effect is to place 

 the substance on a slip of glass, add a drop of glycerin, and 

 heat until the glycerin begins to boil. The glycerin is with- 

 drawn by means of filter paper, and the operation repeated 

 until sufficient transparency is attained. 



ANALYSIS OF FEEDING MEALS 



150. Feeding meals are usually analysed in exactly the 

 same way as oil cakes, excepting that the carbohydrates, and 

 in the case of flour the gluten, are occasionally estimated. 



151. Starch. — This may be estimated roughly by knead- 

 ing 5 grams of the meal with a little water on a piece of linen, 

 such as is used in the estimation of woody fibre, and washing 

 thoroughly with water. The starch will pass through the cloth 

 with the filtrate. This must be allowed to settle, then the 

 starch filtered off on a weighed filter, washed, dried at a low 

 temperature, and weighed. 



152. A more scientific method of procedure is to convert 

 the starch, inuline, and dextrin into sugar, and estimate that as 

 described in paragraphs 82-84. The starch is converted into 

 sugar by means of diastase. 



153. Preparation of Diastase. — Place about 5 lbs. of 

 malt, finely ground, in a large beaker, and just cover it with 



