Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: DATA FOR MILK INSPECTION. VARIATIONS IN COMPOSITION. Average Proportion of Solids in Milk.—The most extensive data on this point are those obtained by Vieth, a summary of whose results, covering a period of eleven years, was published in the Analyst of May, 1892. The total number of samples was 120,540, and although some changes had been made in the methods of analysis since the beginning of the work, the results were recalculated so as to be strictly comparable. The averages of the entire series were as follows :— Fat, 4.1 percent. Non-fatty Solids, 8.8 " Total Solids 12.9 Seasonal Variations in the Composition of Milk.—The diagrammatic synopsis of Vieth's results (Analyst, 1892) shows that a notable variation in the proportion of ingredients occurs during the year. The poorest quality occurs during the first half of the year, especially in April. A low figure is also frequently noted about July. In autumn the quality rises, being highest in October and November. The figures show that the variations in the total solids are due mainly to the variations in fat, but not entirely, for an increase in the proportion of fat is usually attended by a slight increase in the non-fatty solids. The earlier tendency was to assign too high a limit for the non.fatty solids, since this figure was obtained by methods which failed to extract all the fat. In applying, therefore, the more modern processes, normal milk will be found to yield a figure for the non.fatty solids decidedly below the extreme limit of 9.5 per cent. Even nine per cent. for the non.fatty solids is more than is usually present. While it may be permissible in special cases, such as the purchase of milk under contract, or in the operation of a large dairy, to reject samples which yield below nine per ce...