LETTER OF TRAXSM1TTAL 



U. S. DEPARTMENT OF AGRICULTURE, 



BUREAU OF CHEMISTRY, 

 '\Yas7iington j D. C. } January 1-5, 1909. 



SIR: I have the honor to submit for your inspection and approval 

 a report on a phosphorus metabolism experiment conducted by 

 F. C. Cook under the supervision of the Chief of Bureau. The report 

 covers an experiment in rabbit feeding, extending over a period of 

 six months, during which organic and inorganic phosphorus were fed, 

 and includes calcium, magnesium, and total and ether-alcohol soluble 

 phosphorus balances. At the conclusion of the experiment, com- 

 plete analyses were made of the bodies of the rabbits, also of normal 

 rabbits, which furnish some valuable data. Although the number 

 of experiments is limited, -the complete review of the literature bear- 

 ing on the subject, which is included in this paper, greatly enhances 

 its value and the interest both in this country and abroad in the 

 relative value of the organic and inorganic forms of phosphorus, 

 iron, etc., in the body economy makes the issuance of this contribu- 

 tion on the subject advisable. 



I recommend that the manuscript be published as Bulletin 123 of 

 the Bureau of Chemistry. 

 Respectfully, 



IT. W. WILEY, Chief. 

 Hon. JAMES WILSON. 



Secretary of Agriculture. 

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