158 H. S. H. WARDLAW, 
of the freezing point of the milk due to the splitting up of 
lactose is negligible in the present case. 
The effect of the removal of different amounts of suspended 
matter from milk by spinning in the centrifuge on the 
acidity of the liquid remaining has also been determined. 
Table II. 
Effect of removal of varying amounts of suspended matter on the acidity 
of the remaining milk. 
Milk. Time Spun. Acidity. 
44 ee M6 
1 hour 16:95 
Bere 17°25 
pene 16°95 
45 ar 18-4 
1 hour 17°45 
Dr a 17-9 
3 18:1 
The amount of substance removed from the milk by 
spinning for periods up to three hours (about 0°1 gm.) has 
therefore very little effect on the acidity of the milk. The 
amount of substance removed from the milk in this time 
is about 1/14 of the solids not fat of milk. Removal of the 
whole of the suspended matter of milk by filtration through 
porcelain has been shown by Professor Chapman (1908) to 
reduce the acidity of milk to one-third of its original value- 
2. Rate of Deposition. 
The milk was spun in the present experiments at 2000 
revolutions per minute in flat-bottomed cylindrical glass 
tubes 14 cm. deep and containing 100 cc. The distance of 
the bottom of the centrifuge tubes from the axis of the 
centrifuge was 22cm. The deposit forms a fairly coherent 
layer on the bottom of the vessel, from which the super- 
fiuid can be poured off without disturbing the deposit. The 
weight of a deposit was determined by transferring it toa 
