. Milk. Milk. PHYSICAL AND CHEMICAL EXAMINATION OF MILK 159 prevent choking the opening (Figs. 47, 48). The acid should be poured into the bottle with the same care as the milk. The temperature of milk and the acid before mixing should be about 21° C. If much higher the mixture is liable to boil and foam will escape. The specific gravity of the acid should be to Com- mercial sulphuric acid has a specific gravity of This is cor- rected by pouring the acid into a small volume of water and meas- uring the specific gravity after the mixture has cooled. It is important that the aci
. Milk. Milk. PHYSICAL AND CHEMICAL EXAMINATION OF MILK 159 prevent choking the opening (Figs. 47, 48). The acid should be poured into the bottle with the same care as the milk. The temperature of milk and the acid before mixing should be about 21° C. If much higher the mixture is liable to boil and foam will escape. The specific gravity of the acid should be to Com- mercial sulphuric acid has a specific gravity of This is cor- rected by pouring the acid into a small volume of water and meas- uring the specific gravity after the mixture has cooled. It is important that the acid should have a definite strength. If too strong, some of the milk solids char and black flakes collect. Fig. 46.—Types of cream and milk test bottles, showing fat columns, menis- cuses, etc. (Bulletin No. 58, B. A. I.) at the bottom of the fat column. If the acid is too weak, the casein may not dissolve completely and the fat is cloudy, or some undissolved casein gathers at the lower end of the fat column. Reading cannot be accurate when the column of fat is not clear and well defined. Charring can be prevented by using a smaller quan- tity of acid, but it is better still to add 2 of an 80 per cent, gly- cerin solution to the milk and mix before the acid is run in. When the acid is too weak a larger quantity than will usually give satisfactory results. Sulphuric acid must be kept in well- closed bottles, otherwise moisture from the air is absorbed and the acid becomes weaker. The specific gravity of the acid is tested with an Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Heinemann, Paul Gustav. Philadelphia and London, W. B. Saunders Company
Size: 1933px × 1293px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorheineman, bookcentury1900, bookdecade1910, bookyear1919
