840 THE VARIABILITY OF COWS' MILK, i., 



is not from zero to the maximal value, but from the density of 

 water to this value. 



Similarly, the greatest range of the percentage of water in the 

 milk is nut from zero to 100%, but from the minimal percentage 

 to this value, and the relative variation is the same as that cal- 

 culated for the range of the i^ercentage of total solid matter. 



The above results show that the greatest relative variation of the 

 values of the quantities observed is in the weight of fat obtained 

 at a milking. This weight varies from 416 to 53 gm. The maxi- 

 mal weight is nearly 8 times the minimal, and the relative range 

 is 2. 



The quantity having the least relative variation is the depression 

 of freezing point of the milk, for which the value is 0084. For 

 the weight of fat, the relative variation is more than 20 times as 

 great as this. 



The greatest relative variation of the percentage of a constituent 

 of milk is that shown by the protein, in which it is 1-5. The per- 

 centage of total solid matter shows the least relative variation, the 

 value in this case being 0-45. 



Among the single constituents of the milk, the least relative 

 variation is that shown by the lactose, in which it amounts to 0-59. 

 The relative variation of the percentage of fat is 10, or nearly 

 double that of the lactose. 



In the following Table are given the mean values of the com- 

 position and properties of the samples of milk obtained at the 

 same milkiugs. Each mean figure, except the fii^st two, is for the 

 milk of 12 cows; the first two series of mean values are for the 

 milk of 11 cows. From these figures, comparisons may be made of 

 the average milk obtained from ismall herds at single milkings. 

 For the reasons already mentioned, these figures are not neces- 

 sarily identical with the figures for the values of the composition 

 and properties of the mixed milks of the herds. 



The actual and relative variations of the different quantities 

 are given as before. In addition, the ratios of the ranges of 

 variation of the mean figures (Range 2) to the ranges of variation 

 of the individual figures (Range 1) given in the previous Table 

 are also shown. 



