Repository: UIHistories Project: Board of Trustees Minutes - 1890 [PAGE 259]

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UNIVERSITY O F ILLINOIS. INVESTIGATIONS OF " M I L K T E S T S . " Ex-

Bulletin No. 1 0 , p p . 3 2 9 - 3 3 6 .

periment No. 106. The object of t h e investigation was First, To show t h a t dairy cows vary in value to their owners. Some are tke weeds in a corn field, and are kept a t an actual loss; while others pay for liheir keeping and a profit besides. Second, To show t h a t t h e pounds of milk brought to a creamery by its patrons is not t h e most accurate basis upon which to pay for t h e milk, since the butter fat, which alone is of value to the creamery, is not always proportionate to the quantity of milk. Third, A trial of some of t h e methods proposed for analysing or testing milk, t h a t can be easily and quickly mastered by those who wish to use them; and observations on t h e accuracy of results obtained by these methods. In the first division of this investigation the per cent, of fat was determined in the milk of each cow, 38 in all, on three different farms, where, at t h a t season, the cows had pasture feed only. The percentages of butter fat varied from 2.3 to 5, and t h e amounts varied still more widely. In t h e second division of the investigation t h e milk brought during one day by each patron to two creameries was analyzed, 113 tests being made. The record shows t h a t at creamery A the milk brought by one-fifth of t h e patrons contained 3.6 per cent, fat, or 27.7 lb. milk to 1 lb. of butter fat. The amount they brought was nearly one-seventh (14.7 per cent.) of the total receipts of milk, and t h e butter fat it contained was about one-seventh (14.4 per cent.) the total amount received. I n this case, then, it did not make much difference with one-fifth of the patrons whether they were paid per hundred lb. of milk or per lb. of butter fat delivered, as each is nearly t h e same proportion of the total quantity for the day. With t h e other four-fifths of the patrons, however, the proportion is quite irregular. The milk brought by 24 patrons, or nearly one-half of all, was 49.7 per cent, of the total quantity, b u t it contained from 3.7 to 4.0 per cent, of fat and supplied 51.9 per cent, of t h e total butter fat. One-fourth of t h e patrons delivered 26.5 per cent, of the total milk brought; but it contained from 3.2 to 3.5 per cent of fat and supplied only 24.3 per cent, of the total butter fat t h a t day. Besides these already mentioned are a few extremes. The milk supplied by two patrons contained 3.0 and 3.1 per cent, fat, and t h a t supplied by four patrons, from 4.1 to 4.4 per cent, fat, making a difference of 1.4 per cent, between extremes; or t h e richest milk was 47 per cent, richer than t h e poorest. Equally striking illustrations could be drawn from t h e record of creamery B. Eighty per cent, of the patrons supplied milk ranging from 3.2 to 3.8 per cent, of fat, but the milk brought by one patron ran as low as 2.3 per cent, and that brought by another as high as 4.6 per cent, of fat; t h a t is, one contained just twice as much butter fat in 100 lb. of milk. If t h e richer milk is received at $1 per 100 lb., for t h e poorer but 50 cts. per 100 lb. should be paid. I n t h e third division of this investigation an examination was made of five methods or systems, proposed during t h e last two years to be used for analyzing or testing milk by persons not chemists. 1. "A new method for determining fat in milk," by F . G. Short. (Bulletin No. 16, July, 1888, A. E. S., Univ. of Wis.) 2. "A new volumetric method for t h e estimation of fat in milk, skimmed milk, buttermilk, and cream," by C.'L. Parsons. (Ann. BepH, N. H. A. E. S., 1888, p. 69.) 3. "A new method of milk analysis for t h e use of dairymen," by G. H. Eailyer and J. T. Willard. (Ann. Be'pt Kas. A. E. S., 1888, p. 149.) 4. "A new process for determining t h e per cent, of fat in milk, cream, or skim milk," by C. B. Cochran. Patented. (Jour. Analytical Chemistry, Vol. III., p. 381.)