Isolation of Toxic Principles of Coffee. 141 



percolate was then concentrated and made strongly alkaline 

 and steam distilled. From the distillate we recovered pyridine 

 in the pure form. 



In order to ascertain the activity of the concentrate in terms 

 of its physiological action, the concentrate, which was the 

 result of the dry distillation of coffee at a definite temperature 

 and diminished pressure, was collected, hermetically sealed in 

 glass ampules and sent to the laboratories of Parke, Davis & 

 Co., where its toxicity was determined quantitatively by Doctor 

 Hamilton in the biological laboratory of that firm. 



Their report is as follows : "The results of our tests indicate 

 that the minimum lethal dose of the concentrate, administered 

 intraperitoneally, for frogs is 0.03 cc. per gram of body 

 weight; for guinea pigs it is about 0.8 cc. per kilo of body 

 weight." 



We have just sent to the same biological chemist another lot 

 of concentrate to have additional determinations made, i. e., 

 one to show the effect of internal administration by the mouth 

 of the concentrate. 



While coffee contains these toxic principles, it does not 

 necessarily indicate, as some might suppose, that coffee is 

 poisonous. Although some people are so constituted that they 

 cannot use coffee, thousands of others use it without harmful 

 effects, and even seem to receive benefit from its use. There- 

 fore, we should not condemn coffee simply because the toxic 

 principle, which has always existed, has been identified more 

 certainly. 



It might be said, in closing, that it is very probable that 

 this toxic principle can be removed. In fact, a process is now 

 in use (vacuum treatment) by which at least part of this 

 principle is expelled, and by further experimentation the proc- 

 ess can be further improved. It might be mentioned that 

 this process of removing the volatile principle in the coffee is 

 in exact contradiction to the former theory that it was desir- 

 able to retain the volatile principle in the coffee for its sup- 

 posed aromatic effect. 



For valuable collaboration in this work the author is in- 

 debted to his associates. Mr. G. N. Watson and Donald H. 

 Lackey. 



University of Kansas, Lawrence. 



