Artificial Mothers' Milk. 107 



FILLING THE BOTTLES WITH HOT WATER. 



After the bottles have been whirled, they should be 

 filled immediately, with boiling water, to the neck, 

 and then whirled again for about one minute, and 

 more water added to bring the fat into the graduated 

 neck. A third whirl of about one minute is given to 

 bring all of the fat into the neck where it can be 

 measured. 



MEASURING THE FAT. 



The fat should be measured im- 

 mediately after the whirling is com- 

 pleted, before it has cooled to a 

 point where it does not flow freely. 

 If many tests are to be made at the 

 same time, better results are ob- 

 tained by setting the bottles in hot 

 water to keep the fat in liquid con- TX£' 

 dition until the readings can be Fig. 13. 



i ^ ^ i-Uo fot In^lrl SMALL WHIRLING MACHINE. 



taken. To measure the tat, noia 

 the bottle in a perpendicular position with the scale 

 on a level with the eye, and observe the divisions 

 which mark the highest and the lowest limits of the 

 fat. The difference between these gives the per cent, 

 of fat directlv. The readings should be taken to half 

 divisions of the scale, or to one-tenth per cent. 



The readings mav be made with less liability of 

 error by measuring the length of the column of fat 

 with a pair of dividers, one point of which is placed 

 at the bottom and the other at the upper limit of the 



