Аннотация:The significance of phosphatase in the physiology of bone has been studied by Robison and his associates and reviewed by Robison 1 and Kay. 2 Kay 2a and others 3 reported an increase of plasma phosphatase in several diseases of bone. We have also found increases of serum phosphatase when generalized osteoporosis was produced experimentally. 4 Some of our other experimental results 5 indicate the untenability of the current view la that an increase of plasma or serum phosphatase is confined almost exclusively to cases of bone disease. However, determinations of serum phosphatase still find their most useful application in the diagnosis of diseases of the bones. Variations of serum phosphatase which are not related to bone metabolism will be considered here only incidentally, and will be discussed elsewhere in greater detail. Kay, 2a Jenner and Kay 3b and others reporting figures for plasma phosphatase in health and disease used Kay's 6 or Jenner and Kay's 3b method of determination. The