Shhehy — Variation of the Constituent Substances of Cows' Milk. 575 



From the figures obtained, the morning, evening, and total daily solids 

 and daily fat were calculated : the solids-not-fat were obtained by subtracting 

 the total fat from the total solids, and the water by taking the total solids 

 from the total milk. Table I (pp. 582-584) gives the accumulated data from 

 one of the cows — 155 — and diagram I (p. 576) is a graphical representation 

 of the total milk, total water, total solids other than fat, and total fat in the 

 milk of the same cow during successive days for the entire period. The table 

 represents one-twelfth of the data, and the graphs one-twelfth of the 

 figures from which the conclusions below are drawn. The ordinates of 

 the diagrams are so scaled that in each constituent part, as well as in the 

 total milk, the percentage fluctuation is represented by a line equal in length 

 to that representing a similar percentage fluctuation in the others. Thus, a 

 50 per cent, increase in 30 pounds of milk, containing approximately T05 

 pound of fat, 27 pounds of solids-not-fat. and 26 - 25 pounds of water, would 

 give the following figures:— milk, 45 pounds; fat, T57 pounds; solids-not- 

 fat, 4V05 pounds; and water, 39'37 pounds. On diagram I, which represents 

 figures approximating to the above, the 50 per cent, increase in each case is 

 represented by similar lengths of ordinate. The comparative lengths of line 

 joining any two successive days on the different curves in the same sheet give 

 empirically the exact comparative variations in the various parts. 

 From the diagrams, the following observations can be made : — 

 (i) The daily variation in water is approximately equal and practically 

 similar to that in the total milk. 



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