In 1935 Dam1 of Copenhagen observed that newly hatched chicks maintained on a diet which was deficient in certain fat-soluble materials, but otherwise adequate in respect to protein, minerals and all known vitamins, suffered from a fatal hemorrhagic diathesis characterized by bleeding from the pinfeathers, hemorrhages into the subcutaneous tissues and muscles and gizzard erosions. The hemorrhagic tendency in these chicks was associated with, and apparently due to, a fall in the concentration of prothrombin in the blood. The condition could be controlled or prevented by administration of the nonsaponifiable, nonsterol fraction of hog liver fat or by feeding alfalfa.2 The protective, antihemorrhagic factor present in these last mentioned materials was tentatively named by Dam the "koagulations vitamin," or vitamin K.
DISTRIBUTION, PHYSICAL AND CHEMICAL PROPERTIES
Vitamin K, or at least substances possessing similar biologic properties, are widely distributed in nature. In the plant kingdom the distribution appears
SNELL AM. VITAMIN K: ITS PROPERTIES, DISTRIBUTION AND CLINICAL IMPORTANCE: A PRELIMINARY REPORT. JAMA. 1939;112(15):1457–1459. doi:10.1001/jama.1939.62800150002010
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