This book is published by the Medical Research Council and takes up in detail the technic of the tests used in the bacteriologic grading of milk and the interpretation of the tests used in this grading.
The work contains an immense amount of detail. The general conclusions are that all milk should be tested after standing from twelve to eighteen hours at atmospheric temperature. Cleanliness should be judged not by tests on one or two samples but by tests on samples taken frequently and regularly throughout the year. The sediment test, the leukocyte count, determination of the titrable acidity, estimation of the hydrogen ion concentration, the increase in acidity, the bromthymolsulfonphthalein (bromthymol blue) test, the keeping quality test and laboratory pasteurization cannot be regarded as suitable for the routine grading of milk. The test for coliform bacilli is of value only for freshly pasteurized milk. The plate count test is