The development of official or standard methods for various types of laboratory examinations represents a distinct advance from the standpoint of the usefulness of the results obtained. The standard methods for the bacteriological analysis of milk have made it possible to compare, on a satisfactory basis, the results secured in different laboratories and, undoubtedly, have been a factor in extending the use of bacterial counts for the control of milk supplies. The procedure at present required by Standard Methods of Milk Analysis1 for the macroscopic colony count on milk has been developed over a period of years. It is generally recognized that there are other media and incubation conditions which would give higher counts but none of these is at present standard because of the desire to employ a procedure which is easily carried out and comparatively inexpensive
