LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 



Bureau of Chemistry, 

 Washington, D. C, March 25, 1912. 

 Sir: I have the honor to present for your approval a report of an 

 experimental study on the elimination of caffein, conducted in the 

 Pharmacological Laboratory of the Division of Drugs. This work is 

 in continuation of the studies reported in Bulletin 148, on the toxicity 

 of caffein, and is of special interest in connection with certain prob- 

 lems arising under the administration of the food and drugs act, as 

 well as of general scientific and professional value. I recommend 

 that this manuscript be published as Bulletin 157 of the Bureau of 

 Chemistry. 



Respectfully, R. E. Doolittle, 



Acting Chief. 

 Hon. James Wilson, 



Secretary of Agriculture. 



