An interesting and practical point concerning the use of milk in infant-feeding is discussed by Anderson,1 who has recently investigated the relative proportion of bacteria in the top or cream layer and in the skim milk and sediment.
As is well known, writers on infant-feeding commonly advocate the use of the top layer—a third, fourth or fifth—after the milk has stood for several hours whereby different percentages of fat may be obtained, depending on the length of time the milk has stood. Now Anderson by bacteriologic methods shows in a series of experiments that the top layer contains from ten to five hundred times as many bacteria per cubic centimeter as the mixed milk. For example, in thirty samples of bottled milk examined the average number of bacteria in gravity raised cream was 69,211,000 and in the lower layer 4,360,000 per cubic centimeter. A similar but greater difference exists