CHAPTER III. 



MILK-SOLIDS. 



THE first step in dealing with a sample of milk is to insure 

 that it is thoroughly mixed up. This is most conveniently 

 done by pouring it from one vessel to another ; and it is 

 essential to attend to this particular in order to avoid getting 

 either too much or too little cream that is to say, either a 

 greater or less proportion than the sample really contains. 

 It is also well, in this preliminary stage of the inquiry, to 

 make out whether the milk be sour or not, and whether or 

 not it be curdled. If very sour, there is of course a chance 

 of destruction of some of the organic material, and the de- 

 gree of acidity in such a case ought to be measured by means 

 of standard solution of alkali. If the milk be curdled, care 

 will also have to be taken to avoid an unequal distribution 

 of the caseine ; and in cases of this kind, I do not like to use 

 the pipette for measuring off the quantity of milk, but I pre- 

 fer to weigh out the quantity of milk taken for analysis. 



Assuming that the milk is fresh and in good condition, it 

 may be measured in a small pipette vide fig. 



The quantity taken for analysis is five cubic centimetres. 

 Pipettes for the discharge of 5 c. c. may be purchased of 

 Messrs. Townson & Mercer, who supply them graduated very 

 satisfactorily. The pipette should be accurate, within ^^ of a 

 cubic centimetre; and should be tested by being charged with 



