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Evidence for the occurrence of polyphosphates having apparent chain‐lengths ranging from less than 10 to over 5000 orthophosphate units has been found in adult brain as well as in a number of other mammalian tissues which have been examined. There appears to be three times as much polyphosphate in rat brain as there is in rat liver. Adult rat brain appears to contain at least 15 μg of phosphorus as polyphosphate per g of fresh tissue. In addition, neural polyphosphate is extremely labile to catabolic degradation after death whereas hepatic polyphosphate is relatively more stable. The nature of this inorganic polymer was elucidated through use of the technique of 31P nuclear magnetic resonance spectroscopy. Further structural evidence was obtained by application of the isotopic dilution technique to 32P‐labelled neural polyphosphate mixed with an abiotically prepared inorganic polyphosphate. The conditions and rates of hydrolysis of the biological polyphosphate and a non‐biological polyphosphate were comparable.

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The phosphorus of the primitive Earth was present as phosphates. It is strongly probably that a portion of the phosphate was present as condensed phosphates. The primitive Earth was highly deficient in the total available phosphorus until a sufficient quantity of phosphorus weathered from the igneous rocks in which it was entrapped. Approximately three billion years were required for the seas to become saturated. Until this time passed the seas acted as a giant sink for phosphorus, diluting it to the extent that all forms of life were deprived of the vital nutrient. When the seas became saturated, the rate of turn over of the phosphorus increased rapidly. As the seas pulsated, they left the excess precipitate phosphorus as sedimentary rock in locally righ deposits on which life could thrive.