Some Phosphorus Compounds of Milk: The Presence in Milk of Organic Acid-soluble Phosphorus Compounds

Phosphorus Compounds of Milk. V. The Phosphorus Partition in Milk, with Preliminary Observations on Milk Phosphatase

1. Using the method described by Sanders for protein and fat precipitation from cow's milk, a fairly satisfactory method of determining the phosphorus partition in cow's milk has been devised.

2. It is found that the gravimetric procedure of the American Association of Official Agricultural Chemists ((10), p. 3), which was not, in any case, specifically recommended for the analysis of milk, cannot be applied with safety to the determination of inorganic phosphate in filtrates prepared by Sanders' (1932) method, and that the conclusion that there is no appreciable amount of organically combined phosphorus in these filtrates is therefore invalidated.

3. The ester P (organically combined, acid-soluble P) in milk obtained by the usual milking routine varies from 1/7 to 1/4 of the inorganic P of the milk (from 7 to 21 mg. P per 100 c.c. milk).

4. An active phosphatase is present in cow's milky, and brings about changes in the ester P content of the milk on standing, possibly within and certainly without the mammary gland. Like phosphatases of all mammalian tissues, its optimumpH is in the neighbourhood of 9·0. In freshly drawn milk it is working, therefore, considerably on the acid side of its optimum.

5. The phosphoric ester P of the milk appears to vary with the breed of cow, being low in the miiy of Canadian Holstein-Friesian cows and higher in that of Jersey cows.

Herbert Davenport Kay, 9 September 1893--24 November 1976

Herbert Davenport Kay was born at Heaton Chapel, Lancashire, on 9 September 1893. During the last years of his life, he became interested in his family history, constructing detailed family trees and tracing his ancestry to the eighteenth century. The Kay family had moved to Cheadle (Cheshire) from Bury in Lancashire in the early nineteenth century. They were descended from John Kay the inventor, also known as ‘Kay of Bury’ who in 1733 took out a patent for his fly-shuttle and later invented the extended lathe and a card-making machine. On his mother’s side, the Davenports were descended from yeoman farmers in Cheshire. It was a source of quiet amusement to Herbert Kay to learn from his archival searches that one of his maternal great-grandmothers, Mary Barlow ( née Joliffe), was said to be illegitimate. Certainly the sum left to her by her father remained in Chancery because of the absence of a marriage certificate.