Page:Popular Science Monthly Volume 45.djvu/510

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its nutritive qualities. Investigation has demonstrated that milk subjected to lengthy boiling under pressure is in many ways unsuited to the digestion of an infant. Chemical analyses have proved what experience has shown to be the case—namely, that milk sterilized by the higher and prolonged temperature is not fit for administration to an infant. Dr. Henry Chapin, of New York, has been making a study of infant feeding and of children in the Post-graduate Hospital of that city, to which he is attached, and he says, in an article recently published in the New York Medical Journal, that partial sterilization or Pasteurization, to the point of killing the germs only, is necessary and desirable, as a high and continuous temperature produces unfavorable changes in the milk; the fat collects in masses, the albuminoids are changed, the casein is altered, and the digestive action on the casein of sterilized milk is incomplete. Simply

PSM V45 D510 Pasturizing and sterilizing milk.jpg

sufficient heat must be applied to the milk to keep it sweet until the next supply can be procured. Herein lay one of the most frequent sources of trouble in the earlier days of sterilization, caused by lack of exact knowledge in this direction; and in addition to this, when sterilized milk was first introduced, many mothers reasoned that, being sterile, it was a perfect food, and consequently used it without any further preparation, with the natural result of indigestion and all its resultant ailments. It is quite true that milk to be a perfect food must first be sterile, but it must also be assimilable; and to reach this point great care must be given as well to its preparation and administration. Notwithstanding the care exercised by boards of health, it is impossible at any time to be sure of the purity of the milk supply; hence the need is urgent that it be made safe by Pasteurization, which is, in reality, simply subjecting the milk to the lower temperature of 150° to 160° F., instead of 212° F., as was formerly done, and is called thus in deference to Pasteur, who long ago found that the ordinary germs of fermentation and bacteria