162 



PROCEEDINGS OP SECTION B. 



calculated from the 8'5 per cent, solids not tat standard, and in each 

 case the figures for nitrogen and ash indicate that the greater propor- 

 tion of water was actually present. When the milk becomes acid the 

 fermentation causes the splitting up of the larger molecules into a 

 number of smaller molecules, and thus increases the osmotic pressure 

 and lowei's the freezing point. 



I believe a correcting factor has been established for calculating 

 the true freezing point from the freezing point found and the acidity, 

 but I have not been able to obtain the factor, and it is doubtful if it 

 would be reliable, as the fermentation products would most probably 

 vary with the nature of the prevailing; ferment present and the time 

 and temperature of the reaction, and it is not probable that the 

 acidity would in all cases be a true measure of the decrease in freezing 

 point. 



It will be noticed that if the mean result is taken of the added 

 water in all those milks giving less than 8'5 per cent, solids not fat 

 calculated first on the 8'5 basis, and then from the freezing point, 

 the mean added water as determined by the freezing point is 3 per 

 cent, greater than that calculated from the 8'5 standard. 



The whole of the samples quoted were obtained by inspectors in 

 the ordinary manner under the Health Act, and the analyses made in 

 the usual manner. v 



It will be noticed that the fat contents of some of the milks is 

 much higher than is usually recorded. I find in Brisbane that high 

 fat contents are the rule. In February last year, our wettest month, 

 when there was plenty of green grass, and the yield in quantity of 

 milk was therefore above the normal, and the fat supposed to be 

 below normal, the results of the testing of eleven dairies was as 

 under, the milking being done in presence of two inspectors, who also 

 saw the samples were correctly taken : — 



Yields of over 5 per cent, butter fat in samples taken by inspec- 

 tors are by no means uncommon, and samples have been received 

 giving as high as 5 '65 per cent, butter fat. 



