832 THE VARIABILITY OF COWS' MILK, i , 



traction of the percentage of fat, milk-sugar, and ash, from the 

 percentage of total solid matter. The values given for protein and 

 tlie remaining substances are, therefore, subject to the variations 

 of all the values for the percentages of fat, milk-sugar, ash, and 

 solids; and if all these errors happened to fall in the same direc- 

 tion, the corresponding error of the percentage of protein, etc., 

 might amount to as much as 5%. In practice, however, the error.'^ 

 will be more likely to balance one another. The figures for the 

 percentages have been given to the nearest 005. 



Results. 

 The numerical results of the chemical and physical examina- 

 tion of the samples of milk discussed in this paper are given in 

 Table ii. The Table also contains the data for the breed, age, 

 and stage of lactation of the cows from which the samples were 

 obtained. The entries in the sev^eral columns are as follows: — 



(1) Serial number of sample. 



(2) Date of collection. 



(3) Chief strain of breed. 



(4) Number of calf. 



(5) Age of calf in days. 



(6) Weight of sample in kg. 



(7) Density at 25 C. 



(8) Depression of freezing point (A). 



(9) Electrical conductivity in reciprocal ohms x 10~''',at25C. 



(10) Percentages of total solid matter. 



(11) Percentage of water. 



(12) Percentage of fat. 



(13) Percentage of solids not fat (8,n.F.). 



(14) Percentage of lactose. 



(15) Percentage of ash. 



(16) Percentage of protein and extractives. 



