26 



MILK-ANALYSIS. 



that may be employed for the purpose of containing the 

 solution. 



The dish having been weighed, is charged with the 

 ethereal solution, and placed in warm water, whereupon the 

 evaporation of the ether may be made to proceed gently. 

 As the evaporation approaches its termination, a change 

 will be visible in the aspect of the solution. It will become 

 turbid, owing to the trace of water and small quantity of 



alcohol, which gradually predominate over the ether, being 

 incapable of dissolving the fat. When this stage is reached, 

 the dish should be transferred to the water-bath, and heated 

 to 100 C. After being maintained at 100 0. for a short 

 time, the solution will again become clear, owing to the 

 evaporation of the trace of water and alcohol. When this 

 clearness has come on, the fat is dry, and the dish may be 

 removed from the bath, wiped, cooled, and, along with its 

 contents, weighed. The weight of the empty dish being 

 subtracted, the difference is the weight of the fat yielded by 

 the milk. This multiplied by 10 or 20, as the case may be, 

 gives the number of grammes of fat yielded by 100 c. c. of 

 milk. 



