LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 



Bureau of Plant Industry, 



Office of the Chief, 



Washington, D. C, May 2/ h 1907. 



Slr: I have the honor to transmit herewith, and to recommend for 

 publication as Bulletin Xo. 112 of the series of tins Bureau, the 

 accompanying technical manuscript entitled u The Use of Suprarenal 

 Glands in the Physiological Testing of Drug Plants." Tins paper was 

 prepared by Dr. Albert C. Crawford, Pharmacologist in Drug-Plant 

 Investigations, as one of a series of publications on the subject of 

 drug testing, and has been submitted by Dr. Rodney H. True, 

 Physiologist in Charge, with a view to its publication. 



This paper is preliminary to a consideration of the subject of the 

 testing of ergot, one of the most valuable and variable of vegetable 

 drugs. It has been proposed by recent investigators that the most 

 acceptable means of measuring the activity of ergot is to standardize it 

 against a known preparation of the active principle of the suprarenal 

 glands. In order, therefore, to enable us to carry out the ergot test, 

 the presentation of a means of standardizing the active principle of 

 suprarenal glands is a preliminary^ step. 



Among the great advance steps taken by medicine in later years, 

 the attempt to bring medicinal agents to a known and, when possible, 

 uniform standard of action is one of the most important. Many 

 drugs are now standardized by chemical methods and can be admin- 

 istered by the physician in full confidence that his remedy is capable 

 of exerting the desired degree of action. In the case of others in 

 winch the active principles are not as yet known or in which the 

 principle will not admit of isolation, testing by physiological means 

 has come to be recognized as a prime necessity. Since this phase of 

 drug investigations is still young, a considerable diversity in methods 

 exists. It is hoped that this paper, which treats of methods of 

 testing the active principle of suprarenal glands, may contribute 

 toward greater uniformity in this important matter and make more 

 generally available than is now the case the essentials of an important 

 means whereby physiology may serve medicine. 



Respectfully, 



B. T. Galloway, 



Chief of Bureau. 

 Hon. James Wilson, 



Secretary of Agriculture. 



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